Sampling and repeatability in the evaluation of hepatitis C virus genetic variability.

Among the experimental techniques available to study the genetic variability of RNA virus populations, the most informative involve reverse transcription (RT), amplification, cloning and sequencing. The effects of several aspects of these techniques on the estimation of genetic variability in a virus population were analysed. Hepatitis C virus populations from four patients were examined. For each patient, ten series of data derived from independent PCR amplifications of a single RT reaction were obtained. The sample size of each data set was 10 sequences (in nine series) and 100 sequences (in one series). An additional data set derived from an independent RT reaction (about 10 sequences) p…

epiPATH: an information system for the storage and management of molecular epidemiology data from infectious pathogens.

Abstract Background Most research scientists working in the fields of molecular epidemiology, population and evolutionary genetics are confronted with the management of large volumes of data. Moreover, the data used in studies of infectious diseases are complex and usually derive from different institutions such as hospitals or laboratories. Since no public database scheme incorporating clinical and epidemiological information about patients and molecular information about pathogens is currently available, we have developed an information system, composed by a main database and a web-based interface, which integrates both types of data and satisfies requirements of good organization, simple…

Genetic similarity of hepatitis C virus and fibrosis progression in chronic and recurrent infection after liver transplantation

SUMMARY. The effect of hepatitis C virus (HCV) genetic heterogeneity on clinical features of post-transplantation hepatitis C is controversial. Different regions of the HCV genome have been associated with apoptosis, fibrosis, and other pathways leading to liver damage in chronic HCV infection. Besides, differences in immunodominant regions, such as NS3, may influence HCV-specific immune responses and disease outcome. In the liver transplant setting, a recent study has reported a positive association between HCV-1b Core region genetic relatedness 5-year post-transplantation and histological severity of recurrent hepatitis C. We have compared nucleotide sequences of HCV Core, NS3 and NS5b re…

Emergence and spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

A variant of SARS-CoV-2 emerged in early summer 2020, presumably in Spain, and has since spread to multiple European countries. The variant was first observed in Spain in June and has been at frequencies above 40% since July. Outside of Spain, the frequency of this variant has increased from very low values prior to 15th July to 40-70% in Switzerland, Ireland, and the United Kingdom in September. It is also prevalent in Norway, Latvia, the Netherlands, and France. Little can be said about other European countries because few recent sequences are available. Sequences in this cluster (20A.EU1) differ from ancestral sequences at 6 or more positions, including the mutation A222V in the spike pr…

Legionellosis Outbreak Associated with Asphalt Paving Machine, Spain, 2009

From 1999 through 2005 in Alcoi, Spain, incidence of legionellosis was continually high. Over the next 4 years, incidence was lower, but an increase in July 2009 led health authorities to declare an epidemic outbreak. A molecular epidemiology investigation showed that the allelic profiles for all Legionella pneumophila samples from the 2009 outbreak patients were the same, thus pointing to a common genetic origin for their infections, and that they were identical to that of the organism that had caused the previous outbreaks. Spatial-temporal and sequence-based typing analyses indicated a milling machine used in street asphalt repaving and its water tank as the most likely sources. As oppos…

Molecular Phylogenetic Analyses in Court Trials

Molecular phylogenetics allows reconstructing of the genealogy and evolutionary history of organisms from information on their nucleotide or amino acid sequences. When sequences are derived from very fast evolving organisms, such as ribonucleic acid (RNA) viruses, changes accumulate in a few days or weeks, thus allowing the reconstruction of very recent evolutionary events in the history of these populations. One such event is the transmission of one of these viruses, for instance human immunodeficiency virus (HIV) or hepatitis C virus (HCV), from an infected person to another. This occasionally results in a legal demand seeking for compensation and/or punishment for the transmitter. Hence,…

Domain organization and evolution of multifunctional autoprocessing repeats-in-toxin (MARTX) toxin in Vibrio vulnificus.

ABSTRACT The objective of this study was to analyze multifunctional autoprocessing repeats-in-toxin (MARTX) toxin domain organization within the aquatic species Vibrio vulnificus as well as to study the evolution of the rtxA1 gene. The species is subdivided into three biotypes that differ in host range and geographical distribution. We have found three different types (I, II, and III) of V. vulnificus MARTX (MARTX Vv ) toxins with common domains (an autocatalytic cysteine protease domain [CPD], an α / β-hydrolase domain, and a domain resembling that of the LifA protein of Escherichia coli O127:H6 E2348/69 [Efa/LifA]) and specific domains (a Rho-GTPase inactivation domain [RID], a domain of …

One is not enough: On the effects of reference genome for the mapping and subsequent analyses of short-reads.

Mapping of high-throughput sequencing (HTS) reads to a single arbitrary reference genome is a frequently used approach in microbial genomics. However, the choice of a reference may represent a source of errors that may affect subsequent analyses such as the detection of single nucleotide polymorphisms (SNPs) and phylogenetic inference. In this work, we evaluated the effect of reference choice on short-read sequence data from five clinically and epidemiologically relevant bacteria (Klebsiella pneumoniae, Legionella pneumophila, Neisseria gonorrhoeae, Pseudomonas aeruginosa and Serratia marcescens). Publicly available whole-genome assemblies encompassing the genomic diversity of these species…

Evolutionary dynamics of the E1-E2 viral populations during combination therapy in non-responder patients chronically infected with hepatitis C virus subtype 1b.

Abstract Half of the patients chronically infected with hepatitis C virus (HCV) genotype 1 fail to respond to pegylated interferon alpha (PEG-IFN) and ribavirin (RBV) therapy. This study assesses the effects of treatment on the evolution of the E1–E2 viral region in non-responder patients infected with HCV-1b. Twenty-three HCV-1b chronically infected patients were studied retrospectively, including 19 non-responders to PEG-IFN/RBV therapy (11 null-responders and 8 relapsers) in the study group, and 4 untreated patients in the control group. Genetic and phylogenetic analyses of the E1–E2 viral populations were performed at baseline and at the time of treatment failure to assess changes in ge…

Characterization of new recombinant forms of HIV-1 from the Comunitat Valenciana (Spain) by phylogenetic incongruence

Recombination is one of the main processes shaping the evolution of HIV-1, with relevant consequences for its epidemiology. In fact, Circulating and Unique Recombinant Forms (CRFs and URFs) cause 23% of current infections. The routine analyses of antiretroviral resistance yield partial pol gene sequences that can be exploited for molecular epidemiology surveillance but also to study viral diversity and to detect potential recombinant samples. Among the pol sequences derived from a large sample dataset from the Comunitat Valenciana (Spain), we identified nine putative recombinant samples. We aimed at fully characterizing these samples and performing a detailed analysis of the corresponding r…

Allelic age of the USH2A c.2299delG mutation

24 p., figuras y bibliografía

Genetic Characterization of Legionella pneumophila Isolated from a Common Watershed in Comunidad Valenciana, Spain

Legionella pneumophila infects humans to produce legionellosis and Pontiac fever only from environmental sources. In order to establish control measures and study the sources of outbreaks it is essential to know extent and distribution of strain variants of this bacterium in the environment. Sporadic and outbreak-related cases of legionellosis have been historically frequent in the Comunidad Valenciana region (CV, Spain), with a high prevalence in its Southeastern-most part (BV). Environmental investigations for the detection of Legionella pneumophila are performed in this area routinely. We present a population genetics study of 87 L. pneumophila strains isolated in 13 different localities…

Molecular evolution methods to study HIV-1 epidemics

Nucleotide sequences of HIV isolates are obtained routinely to evaluate the presence of resistance mutations to antiretroviral drugs. But, beyond their clinical use, these and other viral sequences include a wealth of information that can be used to better understand and characterize the epidemiology of HIV in relevant populations. In this review, we provide a brief overview of the main methods used to analyze HIV sequences, the data bases where reference sequences can be obtained, and some caveats about the possible applications for public health of these analyses, along with some considerations about their limitations and correct usage to derive robust and reliable conclusions.

Smoking may increase the risk of hospitalization due to influenza.

Background: Smoking may facilitate influenza virus infections and their severity. The objective was to investigate the risk of hospitalization due to influenza in Spanish smokers and ex-smokers. Methods: We carried out a multicentre, case-control study in 2011. Cases [patients a parts per thousand yen 18 years hospitalized > 24 h with real time polymerase chain reaction (RT-PCR)-confirmed influenza] were selected from 29 Spanish hospitals. For each case, we selected an outpatient aged a parts per thousand yen 18 years with RT-PCR-confirmed influenza matched by age (+/- 5 years), date of hospitalization of the case (+/- 10 days) and province of residence. We collected epidemiological variabl…

Genetic Variability of Hepatitis C Virus before and after Combined Therapy of Interferon plus Ribavirin

We present an analysis of the selective forces acting on two hepatitis C virus genome regions previously postulated to be involved in the viral response to combined antiviral therapy. One includes the three hypervariable regions in the envelope E2 glycoprotein, and the other encompasses the PKR binding domain and the V3 domain in the NS5A region. We used a cohort of 22 non-responder patients to combined therapy (interferon alpha-2a plus ribavirin) for which samples were obtained before initiation of therapy and after 6 or/and 12 months of treatment. A range of 25-100 clones per patient, genome region and time sample were sequenced. These were used to detect general patterns of adaptation, t…

Yaws re-emergence and bacterial drug resistance selection after mass administration of azithromycin: a genomic epidemiology investigation

Summary Background In a longitudinal study assessing the WHO strategy for yaws eradication using mass azithromycin treatment, we observed resurgence of yaws cases with dominance of a single JG8 sequence type and emergence of azithromycin-resistant Treponema pallidum subspecies pertenue (T p pertenue). Here, we analyse genomic changes in the bacterial population using samples collected during the study. Methods We did whole bacterial genome sequencing directly on DNA extracted from 37 skin lesion swabs collected from patients on Lihir Island, Papua New Guinea, between April 1, 2013, and Nov 1, 2016. We produced phylogenies and correlated these with spatiotemporal information to investigate t…

Unequal distribution of RT-PCR artifacts along the E1-E2 region of Hepatitis C virus.

Although viral variability studies have focused traditionally on consensus sequences, the relevance of molecular clone sequences for studying viral evolution at the intra-host level is being increasingly recognized. However, for this approach to be reliable, RT-PCR artifacts do not have to contribute excessively to the observed variability. Molecular clone sequences were obtained from an in vitro transcript to estimate the maximum error rate associated to RT-PCR for the Hepatitis C virus (HCV) E1-E2 region. On average, the frequency of RT-PCR errors was one order of magnitude lower than the level of intra-host genetic variability observed in samples from an HCV outbreak. However, RT-PCR err…

Isolation of Four Lytic Phages Infecting Klebsiella pneumoniae K22 Clinical Isolates from Spain

This article belongs to the Special Issue Bacteriophage—Molecular Studies.

Genetic differentiation and structure of Hippocrepis valentina (Leguminosae) populations

We present an analysis of isozyme variability in natural populations of the plant species Hippocrepis valentina (Leguminosae), which is endemic to the eastern Mediterranean coast of Spain and currently has endangered species status. Our results, obtained by starch-gel electrophoresis of 15 loci, show normal levels of variability for species with similar biology. The comparison with the patterns of genetic variability of two closely related species, H. balearica and H. grosii, confirms the taxonomic status of H. valentina as a proper species, independent of H. balearica, as previously suggested. The analysis of population subdivision shows that substantial variation among populations is pres…

MOESM8 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 8. The phylogenetic trees of the tp0136 and tp0548 genes. The phylogenetic trees were constructed using the Maximum Likelihood method based on the Tamura–Nei model. The bar scale represents the number of substitutions per site. The analysis involved 14 TPA nucleotide sequences including eight derived from the Chinese samples: SHC-0, SHD-R, SHE-V, SHG-I2, B3, C3, K3, and Q3. The T. pallidum subsp. pertenue Fribourg-Blanc sequence [1] was used as an outgroup. There were totals of 1547 and 1317 positions in the final dataset for tp0136 and tp0548 genes, respectively. For both genes, two separate clusters were identified: one cluster of Nichols-like TPA strains (TPA Lineage 1), …

A genomic epidemiology investigation of yaws re-emergence and bacterial drug resistance selection

Abstract Background In a longitudinal study assessing the WHO strategy for yaws eradication using mass azithromycin treatment, we observed resurgence of yaws cases with dominance of a single JG8 sequence type and emergence of azithromycin-resistant Treponema pallidum. Here, we analyse genomic changes in the bacterial population using samples collected during the study. Methods We performed whole bacterial genome sequencing directly on DNA extracted from 37 lesion swabs collected from patients on Lihir Island, Papua New Guinea, between 2013 and 2016. We produced phylogenies and correlated these with temporo-spatial information to investigate the source of new cases and the emergence of five …

Prognosis of hospitalized patients with 2009 H1N1 influenza in Spain: influence of neuraminidase inhibitors

The H1N1 influenza pandemic strain has been associated with a poor prognosis in hospitalized patients. The present report evaluates the factors influencing prognosis.A total of 813 patients hospitalized with H1N1 influenza in 36 hospitals (nationwide) in Spain were analysed. Detailed histories of variables preceding hospital admission were obtained by interview, validating data on medications and vaccine with their attending physicians. Data on treatment and complications during hospital stay were recorded. As definition of poor outcome, the endpoints of death and admission to intensive care were combined; and as a further outcome, length of stay was used.The mean age was 38.5 years (SD 22.…

Baseline prediction of combination therapy outcome in hepatitis C virus 1b infected patients by discriminant analysis using viral and host factors.

Background Current treatment of chronic hepatitis C virus (HCV) infection has limited efficacy −especially among genotype 1 infected patients−, is costly, and involves severe side effects. Thus, predicting non-response is of major interest for both patient wellbeing and health care expense. At present, treatment cannot be individualized on the basis of any baseline predictor of response. We aimed to identify pre-treatment clinical and virological parameters associated with treatment failure, as well as to assess whether therapy outcome could be predicted at baseline. Methodology Forty-three HCV subtype 1b (HCV-1b) chronically infected patients treated with pegylated-interferon alpha plus ri…

Comparison of body mass index (BMI) with the CUN-BAE body adiposity estimator in the prediction of hypertension and type 2 diabetes

BACKGROUND: Obesity is a world-wide epidemic whose prevalence is underestimated by BMI measurements, but CUN-BAE (Clínica Universidad de Navarra - Body Adiposity Estimator) estimates the percentage of body fat (BF) while incorporating information on sex and age, thus giving a better match. Our aim is to compare the BMI and CUN-BAE in determining the population attributable fraction (AFp) for obesity as a cause of chronic diseases. METHODS: We calculated the Pearson correlation coefficient between BMI and CUN-BAE, the Kappa index and the internal validity of the BMI. The risks of arterial hypertension (AHT) and diabetes mellitus (DM) and the AFp for obesity were assessed using both the BMI a…

Inference of the Life Cycle of Environmental Phages from Genomic Signature Distances to Their Hosts

The environmental impact of uncultured phages is shaped by their preferred life cycle (lytic or lysogenic). However, our ability to predict it is very limited. We aimed to discriminate between lytic and lysogenic phages by comparing the similarity of their genomic signatures to those of their hosts, reflecting their co-evolution. We tested two approaches: (1) similarities of tetramer relative frequencies, (2) alignment-free comparisons based on exact k = 14 oligonucleotide matches. First, we explored 5126 reference bacterial host strains and 284 associated phages and found an approximate threshold for distinguishing lysogenic and lytic phages using both oligonucleotide-based methods. The an…

Genetic variability in hepatitis C virus and its role in antiviral treatment response

Summary.  Hepatitis C virus (HCV) is a major health problem worldwide, infecting an estimated 170 million people. The high genetic variability of HCV contributes to the chronicity of hepatitis C. Here, we report results from a large-scale sequence analysis of 67 patients infected with HCV genotype 1, 23 with subtype 1a and 44 with subtype 1b. Two regions of the HCV genome were analysed in samples prior to combined therapy with alpha interferon plus ribavirin, one compressing the hypervariable regions (HVR1, HVR2 and HVR3) of the E2 glycoprotein and another one including the interferon-sensitive determining region (ISDR) and the V3 domain of the NS5A protein. Genetic diversity measures showe…

MOESM2 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 2. Mapping statistics of input read pairs mapped to the reference genomes. Sequencing reads derived from the Chinese strain SRA data were mapped to the Treponema pallidum subsp. pallidum (TPA) SS14 and Nichols reference genomes [6] and to the rabbit genome (Statistics was calculated from post-processed mappings; repetitive and homologous sequences and PCR duplicated reads were excluded from the statistics).

Molecular epidemiology and forensic genetics: application to a hepatitis C virus transmission event at a hemodialysis unit.

Molecular phylogenetic analyses are frequently used in epidemiologic testing, although only occasionally in forensics. Their acceptability is hampered by a lack of statistical confidence in the conclusions. However, maximum likelihood testing provides a sound statistical framework for the testing of phylogenetic hypotheses relevant for forensic analysis. We present the results of applying this method to a small hepatitis C outbreak produced in a hospital hemodialysis unit that involved 6 patients. Polymerase chain reaction products from a 472-nt fragment of the E1-E2 region, including the hypervariable region, HVR-1, of the hepatitis C virus genome were cloned, and an average of 10 clones/p…

Knowledge of and attitudes to influenza in unvaccinated primary care physicians and nurses

Primary healthcare workers, especially nurses, are exposed to the vast majority of patients with influenza and play an important role in vaccinating patients. Healthcare workers' misconceptions about influenza and influenza vaccination have been reported as possible factors associated with lack of vaccination. The objective of this study was to compare the characteristics of unvaccinated physicians and unvaccinated nurses in the 2011-2012 influenza season. We performed an anonymous web survey of Spanish primary healthcare workers in 2012. Information was collected on vaccination and knowledge of and attitudes to the influenza vaccine. Multivariate analysis was performed using unconditional …

Recombination drives genome evolution in outbreak-related Legionella pneumophila isolates.

Legionella pneumophila is a strictly environmental pathogen and the etiological agent of legionellosis. It is known that non-vertical processes have a major role in the short-term evolution of pathogens, but little is known about the relevance of these and other processes in environmental bacteria. We report the whole-genome sequencing of 69 L. pneumophila strains linked to recurrent outbreaks in a single location (Alcoy, Spain) over 11 years. We found some examples where the genome sequences of isolates of the same sequence type and outbreak did not cluster together and were more closely related to sequences from different outbreaks. Our analyses identify 16 recombination events responsibl…

Transmission of human immunodeficiency virus Type-1 by fresh-frozen plasma treated with methylene blue and light

BACKGROUND The risk of transfusion-transmitted infection (TTI) has been minimized by introduction of nucleic acid testing (NAT) and pathogen inactivation (PI). This case report describes transmission of human immunodeficiency virus Type 1 (HIV-1) to two recipients despite these measures. STUDY DESIGN AND METHODS In March 2009 a possible TTI of HIV-1 was identified in a patient that had received pooled buffy coat platelet concentrate (BC-PLT) in November 2005. The subsequent lookback study found two more patients who had received methylene blue (MB)-treated fresh-frozen plasma (FFP) and red blood cells (RBCs) from the same donation. In November 2005 the donor had tested negative for both HIV…

The impact of virus population diversity on the dynamics of cytomegalovirus DNAemia in allogeneic stem cell transplant recipients

Mixed cytomegalovirus (CMV) infections are associated with delayed viral clearance in solid organ transplant recipients. We investigated whether this could be extrapolated to allogeneic stem cell transplant (allo-SCT) recipients. A total of 48 plasma specimens, obtained during 29 episodes of active CMV infection in 25 non-consecutive allo-SCT patients, were analysed. Baseline blood specimens, drawn shortly prior to the inception of pre-emptive antiviral therapy (pre-treatment specimen; n=29), as well as follow-up samples obtained either after the initiation of antiviral therapy (post-treatment specimen; n=15) or during recurrent episodes (n=4) were analysed. Plasma CMV DNA loads were quanti…

Is there a widespread clone of Serratia marcescens producing outbreaks worldwide?

[Background]: Serratia marcescens frequently causes outbreaks in healthcare settings. There are few studies using high-throughput sequencing (HTS) that analyse S. marcescens outbreaks. We present the analysis of two outbreaks in neonatal intensive care units (NICUs) in hospitals from the Comunitat Valenciana (CV, Spain) and the impact of using different reference genomes.

Evolutionary history of the OmpR/IIIA family of signal transduction two component systems in Lactobacillaceae and Leuconostocaceae

15 pages, 3 tables, 7 figures.

The power and limitations of genomic surveillance of bacteria.

Prephenate dehydratase from the aphid endosymbiont (Buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine.

ABSTRACT Buchnera aphidicola , the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. We have cloned and sequenced a region of the genome of B. aphidicola isolated from Acyrthosiphon pisum which includes the two-domain aroQ/pheA gene. This gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l -phenylalanine biosynthesis. Two changes involved in the overproduction of this amino acid have been detected. First, the absence of an attenuator region suggests a constitutive expression of this gene. Second, the regulatory domain of the Buchnera prephenate de…

Sociodemographic Factors and Clinical Conditions Associated to Hospitalization in Influenza A (H1N1) 2009 Virus Infected Patients in Spain, 2009–2010

The emergence and pandemic spread of a new strain of influenza A (H1N1) virus in 2009 resulted in a serious alarm in clinical and public health services all over the world. One distinguishing feature of this new influenza pandemic was the different profile of hospitalized patients compared to those from traditional seasonal influenza infections. Our goal was to analyze sociodemographic and clinical factors associated to hospitalization following infection by influenza A(H1N1) virus. We report the results of a Spanish nationwide study with laboratory confirmed infection by the new pandemic virus in a case-control design based on hospitalized patients. The main risk factors for hospitalizatio…

An 18S rDNA-Based Molecular Phylogeny of Aphidiinae (Hymenoptera: Braconidae)

We have obtained a molecular phylogeny of the subfamily Aphidiinae (Hymenoptera: Braconidae) by sequencing the 18S rDNA in 37 aphidiine taxa. Approximately 1857 nucleotides were sequenced in each species. Evolutionary relationships were established by comparing the results of maximum-parsimony, maximum-likelihood, and distance analyses. The most variable region of this gene, V4 (approx 403 nucleotides), was employed to establish the basality of the tribe Ephedrini within this subfamily. All phylogenetic reconstructions yielded trees with very similar topologies that confirmed the existence of two of the four traditionally accepted tribes, Ephedrini and Praini, but questioned the existence o…

Core and Accessory Genome Analysis of Vibrio mimicus

© 2021 by the authors.

No Major Host Genetic Risk Factor Contributed to A(H1N1)2009 Influenza Severity

Garcia-Etxebarria, Koldo et al.

Combined Therapy of Interferon Plus Ribavirin Promotes Multiple Adaptive Solutions in Hepatitis C Virus

Hepatitis C virus (HCV) presents several regions involved potentially in evading antiviral treatment and host immune system. Two regions, known as PKR-BD and V3 domains, have been proposed to be involved in resistance to interferon. Additionally, hypervariable regions in the envelope E2 glycoprotein are also good candidates to participate in evasion from the immune system. In this study, we have used a cohort of 22 non-responder patients to combined therapy (interferon alpha-2a plus ribavirin) for which samples obtained just before initiation of therapy and after 6 or/and 12 months of treatment were available. A range of 25-100 clones per patient, genome region and time sample were obtained…

Immunological response against SARS-CoV-2 following full-dose administration of Comirnaty® COVID-19 vaccine in nursing home residents

6 páginas, 2 figuras, 3 tablas. Se puede acceder al texto completo de este artículo desde PubMedCentral: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8490129 . Los datos de investigación utilizados en el mismo, se encuentran disponibles en: https://doi.org/10.1016/j.cmi.2021.09.031.

Epidemiological, clinical and genomic snapshot of the first 100 B.1.1.7 SARS-CoV-2 cases in Madrid

A new SARS-CoV-2 variant, B.1.1.7, emerged in September in the UK, and is responsible for 76.6% of COVID-19 cases.1 This variant has also been reported in another 45 countries, 17 of them European.2,3 B.1.1.7 is considered to have higher transmissibility.4 It carries an unusually high number of specific mutations/deletions, 18, mostly non-synonymous and eight concentrate in the S gene,5 including several which might have relevant functional roles. The 69/70 deletion may be associated to immune response evasion6 and the N501Y substitution increases the affinity to the ACE2 receptor.7 These findings have raised the alarm of having to face a new variant with the potential to accelerate the spr…

Onychomadesis Outbreak in Valencia, Spain Associated with Hand, Foot, and Mouth Disease Caused by Enteroviruses

This report evaluates the June 2008 onychomadesis outbreak in Valencia, Spain. The study sample consisted of 221 onychomadesis cases and 77 nonaffected individuals who lived close to those affected. We collected data on dietary variables, hygiene products, and individual pathological histories. Feces and blood specimens were collected from 44 cases and 24 controls to evaluate exposure to infectious agents. Pathological background data revealed a high frequency (61%) of hand, foot, and mouth disease among the onychomadesis cases. Coxsackievirus A10 was the most commonly detected enterovirus in both case and control groups (49%). Other enteroviruses such as coxsackieviruses A5, A6, A16, B1, a…

Geographical and temporal structures of Legionella pneumophila sequence types in comunitat valenciana (Spain), 1998 to 2013

ABSTRACT Legionella pneumophila is an accidental human pathogen associated with aerosol formation in water-related sources. High recombination rates make Legionella populations genetically diverse, and nearly 2,000 different sequence types (STs) have been described to date for this environmental pathogen. The spatial distribution of STs is extremely heterogeneous, with some variants being present worldwide and others being detected at only a local scale. Similarly, some STs have been associated with disease outbreaks, such as ST578 or ST23. Spain is among the European countries with the highest incidences of reported legionellosis cases, and specifically, Comunitat Valenciana (CV) is the se…

Different Within-Host Viral Evolution Dynamics in Severely Immunosuppressed Cases with Persistent SARS-CoV-2

12 páginas, 2 figuras, 1 tabla.

The genome sequence of Blochmannia floridanus: Comparative analysis of reduced genomes

Bacterial symbioses are widespread among insects, probably being one of the key factors of their evolutionary success. We present the complete genome sequence of Blochmannia floridanus , the primary endosymbiont of carpenter ants. Although these ants feed on a complex diet, this symbiosis very likely has a nutritional basis: Blochmannia is able to supply nitrogen and sulfur compounds to the host while it takes advantage of the host metabolic machinery. Remarkably, these bacteria lack all known genes involved in replication initiation ( dna A, pri A, and rec A). The phylogenetic analysis of a set of conserved protein-coding genes shows that Bl. floridanus is phylogenetically related to Buch…

MOESM6 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 6. Analysis of indels (deletions/insertions) between SS14-like and Nichols-like TPA strains. The Nichols genome (CP004010.2) [6] was used as a reference for the comparison of TPA strains.

Effectiveness of vaccination with 23-valent pneumococcal polysaccharide vaccine in preventing hospitalization with laboratory confirmed influenza during the 2009-2010 and 2010-2011 seasons

Background: Since influenza predisposes to bacterial pneumonia caused by Streptococcus pneumoniae, studies have suggested that pneumococcal vaccination might reduce its occurrence during pandemics. We assessed the effectiveness of pneumococcal polysaccharide vaccination alone and in combination with influenza vaccination in preventing influenza hospitalization during the 2009–2010 pandemic wave and 2010–2011 influenza epidemic. Methods: We conducted a multicenter case-control study in 36 Spanish hospitals. We selected patients aged ≥ 18 y hospitalized with confirmed influenza and two hospitalized controls per case, matched according to age, date of hospitalization and province of residence.…

Characterization of 10 trinucleotide microsatellite loci in the Critically Endangered Pyrenean yam Borderea chouardii (Dioscoreaceae)

The low levels of allozymic variability found in the Critically Endangered Borderea chouardii prompted us to develop microsatellite markers to assess the genetic variability and population structure for the adequate conservation management of this species. A (CTT) n enriched partial genomic library was constructed. Ten polymorphic microsatellite loci were isolated from it, rendering 51 alleles in 47 individuals analysed. The allelic pattern observed for all of the loci with more than two alleles suggests that B. chouardii is tetraploid.

Clinical relevance of genetic heterogeneity in HCV

Infection by HCV affects an estimated 170 million people worldwide and it represents one of the major causes of liver transplantation and a heavy burden to healthcare systems. As with many other RNA viruses, HCV is characterized by very high levels of genetic variation, which have been associated to differences in disease progression and efficiency of antiviral treatment. Studies show many contradictory results and little consensus on such associations. Nevertheless, some general guidelines translating research results to clinical practice have been postulated. Here, we review the main research results obtained on HCV variation so far and explore the reasons for their lack of congruence und…

Identification of a large, fast-expanding HIV-1 subtype B transmission cluster among MSM in Valencia, Spain

We describe and characterize an exceptionally large HIV-1 subtype B transmission cluster occurring in the Comunidad Valenciana (CV, Spain). A total of 1806 HIV-1 protease-reverse transcriptase (PR/RT) sequences from different patients were obtained in the CV between 2004 and 2014. After subtyping and generating a phylogenetic tree with additional HIV-1 subtype B sequences, a very large transmission cluster which included almost exclusively sequences from the CV was detected (n = 143 patients). This cluster was then validated and characterized with further maximum-likelihood phylogenetic analyses and Bayesian coalescent reconstructions. With these analyses, the CV cluster was delimited to 11…

Evolutionary and phenotypic characterization of spike mutations in a new SARS-CoV-2 Lineage reveals two Variants of Interest

Molecular epidemiology of SARS-CoV-2 aims to monitor the appearance of new variants with the potential to change the virulence or transmissibility of the virus. During the first year of SARS-CoV-2 evolution, numerous variants with possible public health impact have emerged. We have detected two mutations in the Spike protein at amino acid positions 1163 and 1167 that have appeared independently multiple times in different genetic backgrounds, indicating they may increase viral fitness. Interestingly, the majority of these sequences appear in transmission clusters, with the genotype encoding mutations at both positions increasing in frequency more than single-site mutants. This genetic outco…

Complete genome of a European hepatitis C virus subtype 1g isolate: phylogenetic and genetic analyses

Abstract Background Hepatitis C virus isolates have been classified into six main genotypes and a variable number of subtypes within each genotype, mainly based on phylogenetic analysis. Analyses of the genetic relationship among genotypes and subtypes are more reliable when complete genome sequences (or at least the full coding region) are used; however, so far 31 of 80 confirmed or proposed subtypes have at least one complete genome available. Of these, 20 correspond to confirmed subtypes of epidemic interest. Results We present and analyse the first complete genome sequence of a HCV subtype 1g isolate. Phylogenetic and genetic distance analyses reveal that HCV-1g is the most divergent su…

Ancient bacterial genomes reveal a formerly unknown diversity ofTreponema pallidumstrains in early modern Europe

SummarySexually transmitted (venereal) syphilis marked European history with a devastating epidemic at the end of the 15thcentury, and is currently re-emerging globally. Together with non-venereal treponemal diseases, like bejel and yaws, found in subtropical and tropical regions, it poses a prevailing health threat worldwide. The origins and spread of treponemal diseases remain unresolved, including syphilis’ potential introduction into Europe from the Americas. Here, we present the first genetic data from archaeological human remains reflecting a previously unknown diversity ofTreponema pallidumin historical Europe. Our study demonstrates that a variety of strains related to both venereal…

From phylogenetics to phylogenomics: the evolutionary relationships of insect endosymbiotic gamma-Proteobacteria as a test case.

The increasing availability of complete genome sequences and the development of new, faster methods for phylogenetic reconstruction allow the exploration of the set of evolutionary trees for each gene in the genome of any species. This has led to the development of new phylogenomic methods. Here, we have compared different phylogenetic and phylogenomic methods in the analysis of the monophyletic origin of insect endosymbionts from the gamma-Proteobacteria, a hotly debated issue with several recent, conflicting reports. We have obtained the phylogenetic tree for each of the 579 identified protein-coding genes in the genome of the primary endosymbiont of carpenter ants, Blochmannia floridanus…

Intra- and intergenotypic competition in Drosophila melanogaster: effects of density on larval survival and rate of development

We have examined the effects of density and frequency in the larval competition of Drosophila melanogaster by measuring three fitness components: viability (V), mean development time (MDT) and a combination of these two (E). We have detected (contrary to most published results) non-linear effects of density in single-genotype cultures; in addition, different functions are required to describe the density effects below and above the optimal density. Frequency has also non-linear effects in the two-genotype cultures. Only one polymorphic equilibrium frequency, which is stable, occurs with respect to V; but two polymorphic equilibria, one stable and one unstable, exist with respect to E. The r…

One year into the pandemic: Short-term evolution of SARS-CoV-2 and emergence of new lineages.

The COVID-19 pandemic was officially declared on March 11th, 2020. Since the very beginning, the spread of the virus has been tracked nearly in real-time by worldwide genome sequencing efforts. As of March 2021, more than 830,000 SARS-CoV-2 genomes have been uploaded in GISAID and this wealth of data allowed researchers to study the evolution of SARS-CoV-2 during this first pandemic year. In parallel, nomenclatures systems, often with poor consistency among each other, have been developed to designate emerging viral lineages. Despite general fears that the virus might mutate to become more virulent or transmissible, SARS-CoV-2 genetic diversity has remained relatively low during the first ~…

Managing an Online Survey about Influenza Vaccination in Primary Healthcare Workers

Online surveys are increasingly used due to their speed and efficiency. The aim of this study was to analyze factors that may have contributed to the quality and speed of response of an online survey on influenza vaccination in primary healthcare workers. A multicenter study including family physicians, nurses and pediatricians from primary healthcare teams from seven Spanish Autonomous Communities was designed. The centers were selected by simple random sampling. The survey remained active and accessible for 56 days and four reminders were sent. The odds ratios (OR) and their 95% confidence intervals (CI) were calculated to assess the association of sociodemographic variables and respondin…

Hepatitis C virus early kinetics and resistance-associated substitution dynamics during antiviral therapy with direct-acting antivirals

The emergence of resistance-associated substitutions (RASs) can compromise the high efficacy of direct-acting antivirals (DAAs). Little is known about RASs selection at very early time points during DAA treatment. Therefore, we analyzed the potential emergence of RASs immediately after therapy initiation. Samples of 71 patients treated with different DAAs were collected at baseline, during therapy (hours 4 and 8; days 1-7; weeks 2-4) or until target not detected. HCV-RNA levels were determined by qPCR, and RASs were detected by deep sequencing. Sixty-three (89%) patients achieved a sustained virological response (SVR), 7 (10%) relapsed, and 1 (1%) experienced a breakthrough. Almost all non-…

Estudios de epidemiología molecular en población inmigrante en España

Fundamentos: La epidemiología molecular es una nueva disciplina que permite la integración de la información sobre la variabilidad genética de patógenos infecciosos con su difusión en la población y subgrupos de la misma incluyendo, por ejemplo, las mutaciones de resistencia a antibióticos y antivirales. El objetivo es conocer qué posibles diferencias existe en las características genéticas de los agentes infecciosos que afectan a las poblaciones inmigrante y autóctoctona en España. Métodos: Se revisaron artículos originales publicados entre 1998-2013, con las palabras clave "epidemiología molecular", "tipado molecular", "secuenciación", "inmigrante", "España". Resultados: De un total de 26…

Comparative genomic and phylogenetic analyses of gammaproteobacterial glg genes traced the origin of the Escherichia coli glycogen glgBXCAP operon to the last common ancestor of the sister orders enterobacteriales and pasteurellales

© 2015 Almagro et al. Production of branched α-glucan, glycogen-like polymers is widely spread in the Bacteria domain. The glycogen pathway of synthesis and degradation has been fairly well characterized in the model enterobacterial species Escherichia coli (order Enterobacteriales, class Gammaproteobacteria), in which the cognate genes (branching enzyme glgB, debranching enzyme glgX, ADP-glucose pyrophosphorylase glgC, glycogen synthase glgA, and glycogen phosphorylase glgP) are clustered in a glgBXCAP operon arrangement. However, the evolutionary origin of this particular arrangement and of its constituent genes is unknown. Here, by using 265 complete gammaproteobacterial genomes we have …

Molecular characterization of Treponema pallidum subsp. pallidum in Switzerland and France with a new multilocus sequence typing scheme

Syphilis is an important public health problem and an increasing incidence has been noted in recent years. Characterization of strain diversity through molecular data plays a critical role in the epidemiological understanding of this re-emergence. We here propose a new high-resolution multilocus sequence typing (MLST) scheme for Treponema pallidum subsp. pallidum (TPA). We analyzed 30 complete and draft TPA genomes obtained directly from clinical samples or from rabbit propagated strains to identify suitable typing loci and tested the new scheme on 120 clinical samples collected in Switzerland and France. Our analyses yielded three loci with high discriminatory power: TP0136, TP0548, and TP…

Ancient bacterial genomes reveal a high diversity of Treponema pallidum Strains in early Modern Europe

Syphilis is a globally re-emerging disease, which has marked European history with a devastating epidemic at the end of the 15th century. Together with non-venereal treponemal diseases, like bejel and yaws, which are found today in subtropical and tropical regions, it currently poses a substantial health threat worldwide. The origins and spread of treponemal diseases remain unresolved, including syphilis’ potential introduction into Europe from the Americas. Here, we present the first genetic data from archaeological human remains reflecting a high diversity of Treponema pallidum in early modern Europe. Our study demonstrates that a variety of strains related to both venereal syphilis and y…

On the verge of extinction: genetics of the critically endangered Iberian plant species, Borderea chouardii (Dioscoreaceae) and implications for conservation management

Borderea chouardii is a relictual and dioecious, strictly sexually reproducing, long-living geophyte of the Dioscoreaceae family. Previous biological and demographic studies have indicated the existence of a uniformly distributed panmictic population of this taxon at the southernmost Spanish pre-Pyrenean mountain ranges where it occurs in rather inaccessible crevices of a single limestone cliff. However, individuals of B. chouardii are spatially subdivided into two subpopulations located, respectively, on the upper and lower parts of the cliff, and vertically separated 150 m. Because of its extreme rarity, B. chouardii was the first Iberian taxon to have a specific conservation plan and has…

Hepatitis C virus intrinsic molecular determinants may contribute to the development of cholestatic hepatitis after liver transplantation

Cholestatic hepatitis C (CHC) is a severe form of hepatitis C virus (HCV) infection recurrence that leads to high graft loss rates early after liver transplantation (LT). To investigate the pathogenic mechanisms of CHC, we analysed HCV quasispecies in CHC patients compared to a control group (mild hepatitis C recurrence) by deep pyrosequencing. At the time of LT, NS5B quasispecies complexity was similar between the two groups but, after LT, it decreased more sharply in CHC patients than in the control group. Interestingly, the major variant before LT propagated efficiently and remained as the dominant sequence after LT in 62 % of CHC patients versus 11 % of controls (P=0.031). Sequence anal…

Larval competition in Drosophila melanogaster: effects on development time

The effects on development time of larval competition that is interrupted at different times are analyzed in an experiment with constant larval density and varying proportions of two competing strains. Interruption of competition is carried out by means of the overfeeding technique, which allows for the study of individuals that, after several days under competition stress, either complete their development in crowded conditions or migrate to a vial with fresh food where the rest of their development takes place. Results of mean development time and within-vial variance of development time show that individuals under strong competition stress can arrest their development retaining the capab…

Recombination in viruses: Mechanisms, methods of study, and evolutionary consequences

© 2014 Elsevier B.V. Recombination is a pervasive process generating diversity in most viruses. It joins variants that arise independently within the same molecule, creating new opportunities for viruses to overcome selective pressures and to adapt to new environments and hosts. Consequently, the analysis of viral recombination attracts the interest of clinicians, epidemiologists, molecular biologists and evolutionary biologists. In this review we present an overview of three major areas related to viral recombination: (i) the molecular mechanisms that underlie recombination in model viruses, including DNA-viruses (Herpesvirus) and RNA-viruses (Human Influenza Virus and Human Immunodeficien…

Visualizing knowledge and attitude factors related to influenza vaccination of physicians

To characterize groups of primary healthcare physicians according to sociodemographic data, years of professional experience and knowledge of and attitudes to influenza, and to evaluate differences between groups with respect to influenza vaccination in the 2011-2012 season.We carried out an anonymous web survey of Spanish primary healthcare physicians in 2012. Information on vaccination, and knowledge of and attitudes to influenza was collected. Multiple correspondence analysis and cluster analysis were used to define groups of physicians.We included 835 physicians and identified three types. Type B were physicians with low professional experience of influenza. Types A and C were physician…

Emerging Trends in CRF02_AG Variants Transmission Among Men Who Have Sex With Men in Spain

Mixed infection by Legionella pneumophila in outbreak patients.

During the molecular epidemiological study of a legionellosis outbreak, we obtained sequence based typing (SBT) profiles from uncultured respiratory samples of 15 affected patients. We detected several distinct allelic profiles some of which were a mixture of alleles present in the more common profiles. Chromatograms from the sequences of one patient with mixed profile showed polymorphisms in several positions, which could result from the simultaneous presence of different Legionella variants in the sample. In order to test this possibility, we cloned PCR amplification products from six loci for two patients with a mixed profile and a patient with a pure profile. After obtaining around 20 s…

A Novel Approach to Identify Candidate Prognostic Factors for Hepatitis C Treatment Response Integrating Clinical and Viral Genetic Data

The combined therapy of pegylated interferon (IFN) plus ribavirin (RBV) has been for a long time the standard treatment for patients infected with hepatitis C virus (HCV). In the case of genotype 1, only 38%–48% of patients have a positive response to the combined treatment. In previous studies, viral genetic information has been occasionally included as a predictor. Here, we consider viral genetic variation in addition to 11 clinical and 19 viral populations and evolutionary parameters to identify candidate baseline prognostic factors that could be involved in the treatment outcome. We obtained potential prognostic models for HCV subtypes la and lb in combination as well as separately. We …

Molecular epidemiology and drug-resistance mechanisms in carbapenem-resistant Klebsiella pneumoniae isolated in patients from a tertiary hospital in Valencia, Spain

Abstract Objectives The aim of this study has been to characterize carbapenem-resistant Klebsiella pneumoniae isolates and to determine the resistance mechanisms involved, the clonal relationship between strains and clinical and demographical data of the infected patients. Methods Clinical and demographical data from patients were collected and statistically analysed. Antimicrobial susceptibility testing was performed and resistance genes were detected both phenotypically and genotypically. Conjugation assays were performed to show horizontal transferability of resistance genes. Clonal relationship was also studied. Next-generation sequencing (NGS) was performed to obtain information regard…

Different prognosis in hospitalized patients with influenza one season after the pandemic H1N1 influenza of 2009-2010 in Spain

Background The present report compares prognosis in hospitalized cases with the H1N1 pandemic virus in two seasons. Methods Two series of hospitalized patients with laboratory-confirmed H1N1 pandemic influenza have been compared: 813 in the season 2009–2010 and 707 in the season 2010–2011. A detailed history of variables preceding hospital admission and during hospitalization was obtained by interview and clinical charts. A combined endpoint of death admission to intensive care was used as outcome due to the low number of deaths. Logistic regression was applied in the analysis for adverse outcome. Results Patients of the second season had different characteristics than in the first one (old…

A new subtype of hepatitis C virus genotype 1: complete genome and phylogenetic relationships of an Equatorial Guinea isolate.

Hepatitis C virus (HCV) is the leading cause of chronic liver disease and is associated with hepatocellular carcinoma. However, there have been few studies on the distribution and genetic diversity of HCV isolates in non-developed countries. Here, the complete genome sequence of an HCV genotype 1 isolate from Equatorial Guinea is reported, the first complete HCV-1 genome of African origin. Phylogenetic analysis revealed that this sequence always grouped with sequences of genotype 1, but did not group clearly with any subtype described so far. An analysis of partial NS5B gene sequences with additional sequences of African origin also failed to find close similarities between the new sequenc…

Nunatak survival vs. tabula rasa in the Central Pyrenees: a study on the endemic plant species Borderea pyrenaica (Dioscoreaceae)

14 páginas, 4 figuras, 2 tablas.

MOESM7 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 7. Alignment of tprD/tprD2 alleles. tprD and tprD2 alleles were downloaded from the NCBI GenBank database for each reference Nichols and SS14 TPA strain, CP004010.2 and CP004011.1 [6], respectively. While the Nichols reference genome harbors identical copies of tprC and tprD genes, the SS14 reference genome carries the tprD2 allele, which is not identical to the tprC gene and differs from the tprD allele by roughly 320 nucleotides. As shown in the alignment, we were able to identify the tprD2 allele (in positions 800–1791 according to the SS14 tprD2 allele) among the sequencing reads from the Chinese SRA data. The alignment was performed using SeqMan software (DNASTAR, Madis…

Isolation and Characterization of Two Klebsiella pneumoniae Phages Encoding Divergent Depolymerases

The emergence of multidrug-resistant bacteria is a major global health concern. The search for new therapies has brought bacteriophages into the spotlight, and new phages are being described as possible therapeutic agents. Among the bacteria that are most extensively resistant to current antibiotics is Klebsiella pneumoniae, whose hypervariable extracellular capsule makes treatment particularly difficult. Here, we describe two new K. pneumoniae phages, &pi

Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

[Objective]: Treponema pallidum subsp. pallidum (TPA) is the causative agent of syphilis. Genetic analyses of TPA reference strains and human clinical isolates have revealed two genetically distinct groups of syphilis-causing treponemes, called Nichols-like and SS14-like groups. So far, no genetic intermediates, i.e. strains containing a mixed pattern of Nichols-like and SS14-like genomic sequences, have been identifed. Recently, Sun et al. (Oncotarget 2016. https://doi. org/10.18632/oncotarget.10154) described a new “phylogenetic group” (called Lineage 2) among Chinese TPA strains. This lineage exhibited a “mosaic genomic structure” of Nichols-like and SS14-like lineages.

Overlapping of Independent SARS-CoV-2 Nosocomial Transmissions in a Complex Outbreak

8 páginas, 2 figuras, 1 tabla.

Refined analysis of genetic variability parameters in hepatitis C virus and the ability to predict antiviral treatment response.

Summary.  Hepatitis C virus (HCV) infects approximately 3% of the world population. The chronicity of hepatitis C seems to depend on the level of genetic variability. We have recently (Torres-Puente et al., J Viral Hepat, 2008; 15: 188) reported genetic variability estimates from a large-scale sequence analysis of 67 patients infected with HCV subtypes 1a (23 patients) and 1b (44 patients) and related them to response, or lack of, to alpha-interferon plus ribavirin treatment.. Two HCV genome regions were analysed in samples prior to antiviral therapy, one compressing the three hypervariable regions of the E2 glycoprotein and another one including the interferon sensitive determining region …

MOESM3 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 3. Genome coverage statistics for individual Chinese strains. Sequencing reads derived from the Chinese strains SRA data were mapped to the TPA SS14 and Nichols reference genomes [6]. The number of bases with a coverage depth of 1 or more, number of bases with more than 10× coverage depth and average/median coverage depth are shown. Statistics were calculated from previously post-processed mappings; repetitive and homologous regions and PCR duplicated reads were excluded from statistical analysis.

Molecular evolution and complete genome sequences in forensic analysis: Neisseria gonorrhoeae in a transmission case

Molecular epidemiology and phylogenetic analyses are frequently used in the investigation of viral transmission cases in forensic contexts. Here, we present the methods and results of the analysis of a bacterial transmission in an alleged child abuse case using complete genome sequences obtained by high-throughput sequencing (HTS) methods.

MOESM5 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 5. Number of SNVs from whole genome alignments produced by NUCmer. Only SNVs detected in all analyzed genomes (i.e., positions with the “N” base in any of the compared genomes were not considered) were used in the analysis. Genes tp0433 (arp), tp0470, and tp0897 (tprK) were excluded from analyses. Chinese strains are shown in bold.

Origin and phylogeography of the Chagas disease main vector Triatoma infestans based on nuclear rDNA sequences and genome size

For about half of all Chagas disease cases T. infestans has been the responsible vector. Contributing to its genetic knowledge will increase Our understanding of the capacity of geographic expansion and domiciliation of triatomines. Populations of all infestans subcomplex species, T. infestans, T. delpontei, T. platensis and T. melanosoma and the so-called T. infestans "dark morph", from many South American countries were studied. A total of 10 and 7 different ITS-2 and ITS-1 haplotypes, respectively, were found. The total intraspecific ITS-2 nucleotide variability detected in T. infestans is the highest hitherto known in triatomines. ITS-1 minisatellites, detected for the first time in tri…

Molecular epidemiology of a hepatitis C virus outbreak in a hemodialysis unit.

ABSTRACT We analyzed a hepatitis C virus (HCV) transmission case in the hemodialysis unit of a private clinic by sequencing two genome regions of virus isolates from a number of patients attending this unit and some external controls. The analysis of 337 nucleotides (nt) in the NS5B region did not provide enough resolution to ascertain which patients were actually involved in the outbreak and the potential source. Nevertheless, this region allowed the exclusion of several patients as putative sources of the transmission case based on their genotypes and phylogenetic relationships. On the other hand, the analysis of several 472-nt-long clone sequences per sample in a more rapidly evolving re…

SARS-CoV-2 and COVID-19: A genetic, epidemiological, and evolutionary perspective

In less than five months, COVID-19 has spread from a small focus in Wuhan, China, to more than 5 million people in almost every country in the world, dominating the concern of most governments and public health systems. The social and political distresses caused by this epidemic will certainly impact our world for a long time to come. Here, we synthesize lessons from a range of scientific perspectives rooted in epidemiology, virology, genetics, ecology and evolutionary biology so as to provide perspective on how this pandemic started, how it is developing, and how best we can stop it.

Origin of modern syphilis and emergence of a contemporary pandemic cluster

AbstractSyphilis swept across the world in the 16th century as one of most prominent documented pandemics and is re-emerging worldwide despite the availability of effective antibiotics. Little is known about the genetic patterns in current infections or the evolutionary origins of the disease due to the non-cultivable and clonal nature of the causative bacterium Treponema pallidum subsp. pallidum. In this study, we used DNA capture and next generation sequencing to obtain whole genome data from syphilis patient specimens and from treponemes propagated in laboratory settings. Phylogenetic analyses indicate that the syphilis strains examined here share a common ancestor after the 15th century…

EvalMSA: A Program to Evaluate Multiple Sequence Alignments and Detect Outliers

8 páginas, 3 figuras, 2 tablas.

Analysis of the Overdispersed Clock in the Short-Term Evolution of Hepatitis C Virus: Using the E1/E2 Gene Sequences to Infer Infection Dates in a Single Source Outbreak

Abstract The assumption of a molecular clock for dating events from sequence information is often frustrated by the presence of heterogeneity among evolutionary rates due, among other factors, to positively selected sites. In this work, our goal is to explore methods to estimate infection dates from sequence analysis. One such method, based on site stripping for clock detection, was proposed to unravel the clocklike molecular evolution in sequences showing high variability of evolutionary rates and in the presence of positive selection. Other alternatives imply accommodating heterogeneity in evolutionary rates at various levels, without eliminating any information from the data. Here we pre…

Use of next generation sequencing technologies for the diagnosis and epidemiology of infectious diseases

[ES]: Por primera vez, la tecnología de secuenciación masiva permite acceder a la información genómica a un precio y a una escala tales, que se está implementado en la práctica clínica y epidemiológica rutinaria. Los obstáculos para dicha implementación son todavía muchos. Sin embargo, ya existen muchos ejemplos de las grandes ventajas que supone en comparación con métodos anteriores. Esto es, sobre todo, porque con una sola determinación podemos obtener simultáneamente información epidemiológica del microorganismo causante, así como de su perfil de resistencias, si bien estas ventajas están más o menos desarrolladas según el patógeno considerado. En esta revisión se repasan varios ejemplos…

Evidence of Recombination in Intrapatient Populations of Hepatitis C Virus.

Hepatitis C virus (HCV) is a major cause of liver disease worldwide and a potential cause of substantial morbidity and mortality in the future. HCV is characterized by a high level of genetic heterogeneity. Although homologous recombination has been demonstrated in many members of the family Flaviviridae, to which HCV belongs, there are only a few studies reporting recombination on natural populations of HCV, suggesting that these events are rare in vivo. Furthermore, these few studies have focused on recombination between different HCV genotypes/subtypes but there are no reports on the extent of intra-genotype or intra-subtype recombination between viral strains infecting the same patient.…

Effectiveness of hand hygiene and provision of information in preventing influenza cases requiring hospitalization☆☆☆★

Background The objective of the study was to investigate the effectiveness of non-pharmacological interventions in preventing cases of influenza requiring hospitalization. Methods We performed a multicenter case-control study in 36 hospitals, in 2010 in Spain. Hospitalized influenza cases confirmed by reverse-transcription polymerase chain reaction and three matched controls (two hospital and one community control) per case were selected. The use of non-pharmacological measures seven days before the onset of symptoms (frequency of hand washing, use of alcohol-based hand sanitizers and handwashing after touching contaminated surfaces) was collected. Results We studied 813 cases hospitalized …

Genetic variability of hepatitis C virus non-structural protein 3 and virus-specific CD8+ response in patients with chronic hepatitis C.

Hepatitis C virus (HCV) variation in specific T-cell epitopes may represent a mechanism of viral persistence in chronic infection. We examined the HCV non-structural protein 3 (NS3), including the immunologically relevant epitopes HCV NS3-2 KLVALGINAV (human leukocyte antigen [HLA]-A2-restricted) and HCV NS3-1391 LIFCHSKKK (HLA-A3-restricted), in 22 HLA-A2+ patients with chronic infection. Significant amino acid variation was found in HCV NS3-2 epitope sequences when compared to the HCV-1 prototype virus. Six of the nine different HCV NS3-2 peptide variants were identified in patients with HCV NS3-2-specific CD8+ cells, detected with an HLA-A2 tetramer made with the HCV-1 prototype peptide.…

Direct sequencing of Legionella pneumophila from respiratory samples for sequence-based typing analysis.

ABSTRACT We have developed a procedure to test the efficiency and reliability of sequencing of Legionella pneumophila genes directly from respiratory samples and have compared the results with those derived from cultured isolates. We tried to obtain the nucleotide sequences of six protein-coding loci included in the sequence-based typing scheme for Legionella pneumophila and three intergenic regions from 132 samples corresponding to 106 patients positive for urine antigen. A seminested PCR approach was used to amplify and sequence these nine loci directly from respiratory samples. Nucleotide sequences were directly obtained for 23 Legionella isolates and also for 66 respiratory secretions f…

Effect of antiviral treatment and host susceptibility on positive selection in hepatitis C virus (HCV).

Abstract We have conducted a large sequence study of the E1–E2 and NS5A regions of the HCV, subtypes 1a and b, both in patients previously treated with interferon, and untreated patients, who later responded, or not, to a combination therapy based on interferon plus ribavirin. We have examined the role played by the number of positively selected sites on disease progression and its relationship with several variables such as patients’ age, sex and their risk of acquiring the disease. We have detected three groups of patients that respond or not to combination therapy: responders of intermediate age, older non-responders and young non-responders, they possess an increasing average number of …

Knowledge of and attitudes to influenza in unvaccinated primary care physicians and nurses

Primary healthcare workers, especially nurses, are exposed to the vast majority of patients with influenza and play an important role in vaccinating patients. Healthcare workers' misconceptions about influenza and influenza vaccination have been reported as possible factors associated with lack of vaccination. The objective of this study was to compare the characteristics of unvaccinated physicians and unvaccinated nurses in the 2011-2012 influenza season. We performed an anonymous web survey of Spanish primary healthcare workers in 2012. Information was collected on vaccination and knowledge of and attitudes to the influenza vaccine. Multivariate analysis was performed using unconditional …

High-throughput sequencing (HTS) for the analysis of viral populations

The development of High-Throughput Sequencing (HTS) technologies is having a major impact on the genomic analysis of viral populations. Current HTS platforms can capture nucleic acid variation across millions of genes for both selected amplicons and full viral genomes. HTS has already facilitated the discovery of new viruses, hinted new taxonomic classifications and provided a deeper and broader understanding of their diversity, population and genetic structure. Hence, HTS has already replaced standard Sanger sequencing in basic and applied research fields, but the next step is its implementation as a routine technology for the analysis of viruses in clinical settings. The most likely appli…

Origin of modern syphilis and emergence of a pandemic Treponema pallidum cluster

The abrupt onslaught of the syphilis pandemic that started in the late fifteenth century established this devastating infectious disease as one of the most feared in human history1 . Surprisingly, despite the availability of effective antibiotic treatment since the mid-twentieth century, this bacterial infection, which is caused by Treponema pallidum subsp. pallidum (TPA), has been re-emerging globally in the last few decades with an estimated 10.6 million cases in 2008 (ref. 2). Although resistance to penicillin has not yet been identified, an increasing number of strains fail to respond to the secondline antibiotic azithromycin3. Little is known about the genetic patterns in current infec…

Homologous recombination as a mechanism of genetic changes in bovine parainfluenza-3 virus

Bovine parainfluenza-3 virus (BPIV-3) is one of the main viruses associated with bovine respiratory disease complex (BRDC) worldwide. BPIV-3 infect the bovine respiratory tract causing from subclinical infections to severe pneumonia with significant economic losses in the cattle industry. BPIV-3 is a RNA virus with high genetic variability, nevertheless, the contribution of recombination events to its variability has not been assessed so far. In this study the 25 complete genome sequences (CGS) reported so far and 215 partial sequences of different viral genes of BPIV-3 were analyzed to determine their genotypes and subgenotypes, distribution, and the existence of potential recombination ev…

Study of the Evolutionary Relationships among Limonium Species (Plumbaginaceae) Using Nuclear and Cytoplasmic Molecular Markers

The genus Limonium, due to the patchiness of the natural habitats of its species as well as the high frequency of hybridization and polyploidy and the possibility of reproduction by apomixis, provides an example of all the principal mechanisms of rapid speciation of plants. As an initial study of evolution in this genus, we have analyzed intra- and interspecific variability in 17 species from section Limonium, the largest in the genus, based on RFLPs of cpDNA and nuclear rDNA ITS sequences. In the cpDNA analysis, 21 restriction enzymes were used, resulting in 779 fragments, 490 of which were variable and 339 parsimony informative. L. furfuraceum exhibited two relatively divergent cpDNA hapl…

The role of positive selection in hepatitis C virus

Hepatitis C virus (HCV) is a major health problem worldwide, infecting an estimated 170 million people. In this study, we have employed a large data set of sequences (14,654 sequences from between 25 and 100 clone sequences per analyzed region and per patient) from 67 patients infected with HCV genotype 1 (23 subtype 1a and 44 subtype 1b). For all patients, a sample prior to combined therapy with alpha interferon plus ribavirin was available, whereas for some patients additional samples after 6 or 12 months of treatment were also available. Twenty-seven patients responded to treatment (12 subtype 1a and 15 subtype 1b) and forty patients did not respond to treatment (11 subtype 1a vs. 29 sub…

Molecular epidemiology of HIV-1 subtype B in the Basque Country (Spain)

The goal of this work was to study the HIV-1 subtype B epidemic in the Basque Country (Spain). For this, we used HIV samples submitted for genotypic testing of anti-retroviral resistance mutations from 2005 until 2008. Consequently, 2115 HIV-1 sequences comprising protease and retrotranscriptase (PR/RT) coding regions were analyzed. HIV transmission groups were identified by phylogenetic analysis. The 10 largest such groups were subsequently subjected to Bayesian phylogenetic and coalescent reconstructions, using a relaxed molecular clock model. The results obtained show that these groups have been long-standing: most of them were originated in the late 70s or early 80s, and none after the …

Genomic Analysis of Bacterial Outbreaks

The study of outbreaks of infectious diseases has been revolutionized by the current availability of fast and efficient, high-throughput methods capable of yielding the nucleotide sequence of complete genomes of viruses and bacteria within a few days, or even hours. These methods are replacing previous molecular techniques which have been used for the past 30 years, although many of them are still the usual approach for many such investigations. Here we review the major technologies currently in use for high-throughput sequencing of bacterial genomes emphasizing their advantages and drawbacks for the analysis of outbreaks. The use of more efficient methods does not necessarily mean that all…

Common gene expression strategies revealed by genome-wide analysis in yeast

A comprehensive analysis of six variables characterizing gene expression in yeast, including transcription and translation, mRNA and protein amounts, reveals a general tendency for levels of mRNA and protein to be harmonized, and for functionally related genes to have similar values for these variables.

Topology testing of phylogenies using least squares methods

[Background] The least squares (LS) method for constructing confidence sets of trees is closely related to LS tree building methods, in which the goodness of fit of the distances measured on the tree (patristic distances) to the observed distances between taxa is the criterion used for selecting the best topology. The generalized LS (GLS) method for topology testing is often frustrated by the computational difficulties in calculating the covariance matrix and its inverse, which in practice requires approximations. The weighted LS (WLS) allows for a more efficient albeit approximate calculation of the test statistic by ignoring the covariances between the distances.

Draft genome sequences of Vibrio vulnificus strains recovered from moribund tilapia

Potentially zoonotic Vibrio vulnificus strains were isolated from vibriosis outbreaks occurring on eastern Mediterranean tilapia farms between 2016 and 2019. In this work, the draft genome sequences of three representative isolates are presented.

Analysis of population genetic structure and variability using RAPD markers in the endemic and endangered Limonium dufourii (Plumbaginaceae)

Limonium dufourii (Plumbaginaceae) is a triploid species, with apomictic reproduction, endemic to the east mediterranean coast of Spain, where it is present in only six populations with a few individuals in most of them. L. dufourii is included in the Red List of Endangered Species by the IUCN. Genetic variation and population structure in this species has been studied using RAPDs. Twelve different primers provided 124 reliable bands of which 33 were polymorphic among the 165 individuals analysed. Those polymorphic bands were able to define 44 different patterns, of which all but six were present in only one population. Several methods for statistical evaluation have been used for intra- an…

Patient-to-patient transmission of hepatitis C virus (HCV) during colonoscopy diagnosis

Abstract Background No recognized risk factors can be identified in 10-40% of hepatitis C virus (HCV)-infected patients suggesting that the modes of transmission involved could be underestimated or unidentified. Invasive diagnostic procedures, such as endoscopy, have been considered as a potential HCV transmission route; although the actual extent of transmission in endoscopy procedures remains controversial. Most reported HCV outbreaks related to nosocomial acquisition have been attributed to unsafe injection practices and use of multi-dose vials. Only a few cases of likely patient-to-patient HCV transmission via a contaminated colonoscope have been reported to date. Nosocomial HCV infecti…

Evolution of Snake Venom Disintegrins by Positive Darwinian Selection

PII-disintegrins, cysteine-rich polypeptides broadly distributed in the venoms of geographically diverse species of vipers and rattlesnakes, antagonize the adhesive functions of beta(1) and beta(3) integrin receptors. PII-disintegrins evolved in Viperidae by neofunctionalization of disintegrin-like domains of duplicated PIII-snake venom hemorrhagic metalloproteinase (SVMP) genes recruited into the venom proteome before the radiation of the advanced snakes. Minimization of the gene (loss of introns and coding regions) and the protein structures (successive loss of disulfide bonds) underpins the postduplication divergence of disintegrins. However, little is known about the underlying genetic …

The effect of RNA substitution models on viroid and RNA virus phylogenies.

Abstract Many viroids and RNA viruses have genomes that exhibit secondary structure, with paired nucleotides forming stems and loops. Such structures violate a key assumption of most methods of phylogenetic reconstruction, that sequence change is independent among sites. However, phylogenetic analyses of these transmissible agents rarely use evolutionary models that account for RNA secondary structure. Here, we assess the effect of using RNA-specific nucleotide substitution models on the phylogenetic inference of viroids and RNA viruses. We obtained data sets comprising full-genome nucleotide sequences from six viroid and ten single-stranded RNA virus species. For each alignment, we inferre…

Does the VP1 gene of foot-and-mouth disease virus behave as a molecular clock?

We have carried out a phylogenetic study of the evolution of the VP1 gene sequence from different serological types and subtypes of foot-and-mouth disease virus (FMDV). The maximum-likelihood method developed by Hasegawa and co-workers (Hasegawa et al. 1985) for the estimation of evolutionary parameters and branching dates has been used to decide between alternative models of evolution: constant versus variable rates. The results obtained indicate that a constant rate model, i.e., a molecular clock, seems to be the most plausible one. However, additional information suggests the possibility that the appearance of serotype CS has been accompanied by an episode of rapid evolution (Villaverde …

Phylogenetic analysis of an epidemic outbreak of acute hepatitis C in HIV-infected patients by ultra-deep pyrosequencing.

Abstract Background The incidence of acute hepatitis C (AHC) among HIV-infected men who have sex with men (MSM) has increased significantly in the last 10 years. Several studies point to a social and sexual network of HIV-positive MSM that extends internationally. Objectives The aim of our study was to investigate the dynamics of HCV transmission in an outbreak of AHC in HIV-infected MSM in Barcelona by ultra-deep pyrosequencing. Study design Between 2008 and 2013, 113 cases of AHC in HIV-infected MSM were diagnosed in the Infectious Diseases Unit, Hospital Clinic, Barcelona. Massive sequencing was performed using the Roche 454 GS Junior platform. To define possible transmission networks, m…

Genetic features of Multi Drug Resistant (MDR) Klebsiella pneumoniae and its Plasmids

Klebsiella pneumoniae, a major cause of both hospital and community-acquired infections, is listed by the World Health Organization as a critical priority antibiotic- resistant bacterial pathogen. With the appearance of sequencing techniques such as Next-generation Sequencing (NGS), there is the possibility to obtain the whole genome of the bacteria, getting to know all antimicrobial resistance determinants. The purpose of this study has been to apply this new technology to clinical microbiology, in order to characterize the resistome present in carbapenem-resistant K.pneumoniae strains isolated in a tertiary hospital in Valencia, Spain. A total of 234 isolates were prepared for whole-genom…

Development of microsatellite markers for the critically endangered Limonium dufourii (Girard) Kuntze (Plumbaginaceae)

Limonium dufourii is an endemic plant from the eastern Mediterranean coast of Spain with a triploid chromosome number and apomictic reproduction. We have isolated and characterized 13 polymorphic microsatellite loci from an enriched library in order to investigate its population genetic structure. Simple sequence repeat (SSR) loci were screened in 120 individuals from the six extant populations of this species. They show an average of 5.76 alleles per locus, ranging from 2 to 18, with seven loci exhibiting heterozygosities larger than 0.60. Three loci present one single allele in each individual, whereas one locus presents three alleles in every individual analysed.

Effect of Occupational Exposure on A(H1N1)pdm09 Infection and Hospitalization.

OBJECTIVE To analyze relationships between occupational exposure and influenza infection and hospitalization during the 2009-2010 pandemic wave and the 2010-2011 influenza seasonal epidemic in Spain. METHODS Occupations were classified as high, medium, or low risk of influenza exposure. To assess the risk of infection, 588 outpatient cases of influenza confirmed by reverse-transcription polymerase-chain-reaction (RT-PCR) were compared with 588 outpatients without influenza symptoms. To assess the risk of hospitalization, 337 outpatient influenza cases were compared with 337 inpatient influenza cases. RESULTS The high risk of occupational exposure group was composed only of health care worke…

Molecular Epidemiology and Evolution in an Outbreak of Fulminant Hepatitis B Virus

ABSTRACT In order to establish the transmission pathway for two outbreak patients affected by fulminant hepatitis B (FHB) following a shared period of hospitalization, we sequenced the complete genomes of the hepatitis B viruses (HBV) isolated from them as well as from the suspected common source and 11 additional controls. Phylogenetic and statistical analyses of these sequences revealed that the two FHB patients were indeed infected by a common source and that the fatal development of the disease did not appear to be associated with any mutation previously reported to be related to FHB. These data have also allowed us to estimate the extent and distribution of genetic variability along th…

Evolutionary processes in the emergence and recent spread of the syphilis agent, Treponema pallidum

Abstract The incidence of syphilis has risen worldwide in the last decade in spite of being an easily treated infection. The causative agent of this sexually transmitted disease is the bacterium Treponema pallidum subspecies pallidum (TPA), very closely related to subsp. pertenue (TPE) and endemicum (TEN), responsible for the human treponematoses yaws and bejel, respectively. Although much focus has been placed on the question of the spatial and temporary origins of TPA, the processes driving the evolution and epidemiological spread of TPA since its divergence from TPE and TEN are not well understood. Here, we investigate the effects of recombination and selection as forces of genetic diver…

Recombination in Hepatitis C Virus

Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) …

Ribotyping of Vibrio Populations Associated with Cultured Oysters (Ostrea edulis)

The intraspecific variability of Vibrio splendidus, V. harveyi and V. tubiashii recovered from oysters (Ostrea edulis) collected at the Mediterranean coast near Valencia, Spain, was analyzed by ribotyping. The two former species represented the most abundant ones, and the third one was the only species described as pathogenic for oysters. A total of 115 environmental strains were studied, 84 of V. splendidus, 23 of V. harveyi and 8 of V. tubiashii. Chromosomal DNA was digested with KpnI and hybridized with an oligonucleotide probe complementary to a highly conserved sequence in the 23S rRNA gene. Ribotyping among natural populations of the three species rendered 5 to 9 bands, and showed a h…

Corrigendum: Phylogeny of Vibrio vulnificus From the Analysis of the Core-Genome: Implications for Intra-Species Taxonomy

Vibrio vulnificus (Vv) is a multi-host pathogenic species currently subdivided into three biotypes (Bts). The three Bts are human-pathogens, but only Bt2 is also a fish-pathogen, an ability that is conferred by a transferable virulence-plasmid (pVvbt2). Here we present a phylogenomic analysis from the core genome of 80 Vv strains belonging to the three Bts recovered from a wide range of geographical and ecological sources. We have identified five well-supported phylogenetic groups or lineages (L). LI comprises a mixture of clinical and environmental Bt1 strains, most of them involved in human clinical cases related to raw seafood ingestion. LII is linked to the aquaculture industry and incl…

The population genetics and evolutionary epidemiology of RNA viruses.

Key Points The authors discuss the main mechanisms of RNA virus evolution — mutation, recombination, natural selection, genetic drift and migration, and how these interact to shape the genetic structure of populations.The quasispecies model of RNA virus evolution is explained and the question of whether this model provides an accurate description of RNA virus evolution is discussed.Experiments that can be carried out to test the basic principles of evolutionary theory are briefly described. The authors review what such experiments have told us about virus evolution and, more widely, what these experiments have revealed in terms of general evolutionary principles.RNA viruses evolve quickly, …

Genomic determinants of speciation and spread of the Mycobacterium tuberculosis complex

14 páginas, 6 figuras

Genome-scale analysis of evolutionary rate and selection in a fast-expanding Spanish cluster of HIV-1 subtype F1.

Abstract This work is aimed at assessing the presence of positive selection and/or shifts of the evolutionary rate in a fast-expanding HIV-1 subtype F1 transmission cluster affecting men who have sex with men in Spain. We applied Bayesian coalescent phylogenetics and selection analyses to 23 full-coding region sequences from patients belonging to that cluster, along with other 19 F1 epidemiologically-unrelated sequences. A shift in the overall evolutionary rate of the virus, explained by positively selected sites in the cluster, was detected. We also found one substitution in Nef (H89F) that was specific to the cluster and experienced positive selection. These results suggest that fast tran…

Epidemic dynamics of two coexisting hepatitis C virus subtypes.

Hepatitis C virus (HCV) infection affects about 3 % of the human population. Phylogenetic analyses have grouped its variants into six major genotypes, which have a star-like distribution and several minor subtypes. The most abundant genotype in Europe is the so-called genotype 1, with two prevalent subtypes, 1a and 1b. In order to explain the higher prevalence of subtype 1b over 1a, a large-scale sequence analysis (100 virus clones) has been carried out over 25 patients of both subtypes in two regions of the HCV genome: one comprising hypervariable region 1 and another including the interferon sensitivity-determining region. Neither polymorphism analysis nor molecular variance analysis (att…

A method for determining the position and size of optimal sequence regions for phylogenetic analysis.

The availability of fast and accurate sequencing procedures along with the use of PCR has led to a proliferation of studies of variability at the molecular level in populations. Nevertheless, it is often impractical to examine long genomic stretches and a large number of individuals at the same time. In order to optimize this kind of study, we suggest a heuristic procedure for detection of the shortest region whose informational content can be considered sufficient for significant phylogenetic reconstruction. The method is based on the comparison of the pairwise genetic distances obtained from a set of sequences of reference to those obtained for different windows of variable size and posit…

Genomic Epidemiology of Salmonella Infantis in Ecuador: From Poultry Farms to Human Infections

Salmonella enterica is one of the most important foodborne pathogens around the world. In the last years, S. enterica serovar Infantis has become an important emerging pathogen in many countries, often as multidrug resistant clones. To understand the importance of S. enterica in the broiler industry in Ecuador, we performed a study based on phenotypic and WGS data of isolates from poultry farms, chicken carcasses and humans. We showed a high prevalence of S. enterica in poultry farms (41.4%) and chicken carcasses (55.5%), but a low prevalence (1.98%) in human samples. S. Infantis was shown to be the most prevalent serovar with a 98.2, 97.8, and 50% in farms, foods, and humans, respectively,…

Initial viral load and decay kinetics of SARS-CoV-2 lineage B.1.1.7 in the upper respiratory tract of adults and children

We read with interest the systematic review published by Walsh et al. in the Journal of Infection,1 focusing on the dynamics of SARS-CoV-2 RNA at the upper respiratory tract (URT). In this context, a novel SARS-CoV-2 variant lineage (B.1.1.7), first detected in the UK at the end of 2020 has transmission advantage over other lineages.2 Increased transmissibility of the B.1.1.7 variant has been linked to enhanced ACE2 affinity3 allegedly resulting in higher viral loads in URT, an observation that has been reported in some,3, 4, 5, 6 but not all7 large series published to date. In addition, longer duration of SARS-CoV-2 RNA shedding in URT has been reported in individuals infected by the B.1.1…

Hepatitis C virus and the controversial role of the interferon sensitivity determining region in the response to interferon treatment

The degree of variability of the interferon sensitivity determining region (ISDR) in the hepatitis C virus (HCV) genome has been postulated to predict the response to interferon therapy, mainly in patients infected with subtype 1b, although this prediction has been the subject of a long controversy. This prediction has been tested by analyzing a cohort of 67 Spanish patients infected with HCV genotype 1, 23 of which were infected with subtype 1a and 44 with subtype 1b. A sample previous to therapy with α-interferon plus ribavirin was obtained and several clones (between 25 and 96) including the ISDR were sequenced from each patient. A significant correlation between mutations at the ISDR an…

An unusually high substitution rate in transplant-associated BK polyomavirus in vivo is further concentrated in HLA-C-bound viral peptides

Infection with human BK polyomavirus, a small double-stranded DNA virus, potentially results in severe complications in immunocompromised patients. Here, we describe the in vivo variability and evolution of the BK polyomavirus by deep sequencing. Our data reveal the highest genomic evolutionary rate described in double-stranded DNA viruses, i.e., 10−3–10−5 substitutions per nucleotide site per year. High mutation rates in viruses allow their escape from immune surveillance and adaptation to new hosts. By combining mutational landscapes across viral genomes with in silico prediction of viral peptides, we demonstrate the presence of significantly more coding substitutions within predicted cog…

Influenza vaccination of primary healthcare physicians may be associated with vaccination in their patients: a vaccination coverage study

Background: To assess the contribution of physician-related factors, especially their influenza vaccine status, in the vaccination coverage of their patients. Methods: A study of vaccination coverage was carried out in Spain in 2011–12. The dependent variable (vaccination coverage in patients aged ≥65 years) was obtained from regional records. Information was gathered on the vaccination of physicians through an anonymous web survey. We compared the vaccination coverage of patients with the vaccination of their physicians using the Student t test. Associations were determined using a multilevel regression model. Results: The coverage in patients aged ≥ 65 years was 56.3% and was higher (57.3…

Staphylococcus prevails in the skin microbiota of long-term immunodeficient mice

Summary Host-commensal relationships in the skin are a complex system governed by variables related to the host, the bacteria and the environment. A disruption of this system may lead to new steady states, which, in turn, may lead to disease. We have studied one such disruption by characterizing the skin micro- biota in healthy and immunodepressed (ID) mice. A detailed anatomopathological study failed to reveal any difference between the skin of healthy and ID mice. We sequenced the 16S rDNA V1-V2 gene region to saturation in 10 healthy and 10 ID 8 week- old mice, and found than all of the healthy and two of the ID mice had bacterial communities that were similar in composition to that of h…

POSTMATING ISOLATION ANALYSIS IN FOUNDER-FLUSH EXPERIMENTAL POPULATIONS OF DROSOPHILA PSEUDOOBSCURA.

In this paper, we report a detailed analysis intended to detect postmating barriers in experimental populations of Drosophila pseudoobscura obtained through nine founderflush cycles. The number of offspring produced was determined in three consecutive generations of hybridization. It is found that the evolution of premating barriers, as shown by two of these populations, is not necessarily accompanied by the evolution of postmating ones. Under the founder-flush model of speciation proposed by Carson (1971), the first step in the speciation process is usually thought to be an incidental genetic change through founder effect affecting mating behavior so that sexual premating isolation evolves…

Proper assignation of reactivation in a COVID-19 recurrence initially interpreted as a reinfection

A 77-year-old-male (Case R) who had had a previous diagnosis of mild COVID-19 episode, was hospitalized 35 days later. On Day 23 post-admission, he developed a second COVID-19 episode, now severe, and finally died. Initially, Case R COVID-19 recurrence was interpreted as a reinfection due to the exposure to a SARS-CoV-2 RT-PCR-positive room-mate. However, whole-genome-sequencing indicated that case R recurrence corresponded to a reactivation of the strain involved in his first episode. Case R reactivation had major consequences, leading to a more severe episode, and causing a subsequent transmission to another two hospitalized patients, one of them with fatal outcome.

Whole-genome sequencing of Neisseria gonorrhoeae in a forensic transmission case.

Abstract Molecular epidemiology and phylogenetic analyses are frequently used in the investigation of viral transmission cases in forensic contexts. Here, we present the methods and results of the analysis of a bacterial transmission episode in an alleged child abuse case using complete genome sequences obtained by high-throughput sequencing (HTS) methods. We obtained genomes of Neisseria gonorrhoeae from the victim, the suspect, and 29 unrelated controls. The analysis of the genomes revealed that the victim and suspect isolates had identical sequences in both the bacterial chromosome and the single plasmid present in them. One of the local controls was very similar (differing in only 2 SNP…

Trends in influenza vaccine coverage among primary healthcare workers in Spain, 2008–2011

To evaluate trends in seasonal influenza vaccination coverage in primary healthcare workers (PHCWs) in Spain between 2008 and 2011.We made an anonymous web survey of PHCWs in 2012. Information on attitudes towards and knowledge of influenza vaccine, and immunization in previous seasons was collected. Self-reported vaccination coverage and factors related to vaccination continuity were analysed.Of 5433 workers contacted, 2625 (48.3%) responded to the survey: 47.0% were general practitioners, 10.3% paediatricians and 42.7% nurses. Their reported vaccination rates from seasons 2008-2009 to 2011-2012 decreased over time: 58.4%, 57.4%, 53.2% and 49.3% (linear trend, p0.001). Among workers vaccin…

Population structure and recombination in environmental isolates of Legionella pneumophila

Legionella pneumophila is a water-borne bacteria responsible for most cases of legionellosis, an emerging disease with an increasing incidence in industrialized countries. Although early analysis based on multilocus enzyme electrophoresis (MLEE) described the population structure of this species as clonal, more recent reports have suggested that recombination also contributes to shaping variation across its genome. We report here the results of analysing the nucleotide sequences of 19 loci in 31 environmental samples of L. pneumophila from a small Spanish region (near Alcoi, province of Alicante) where legionellosis has become almost endemic. We analysed the six loci currently incorporated …

Assessing the potential association between SARS-CoV-2 RNA load in the respiratory tract and COVID-19 mortality.

Special Issue on New coronavirus (2019‐nCoV or SARS‐CoV‐2) and the outbreak of the respiratory illness (COVID‐19): Part‐XI

Risk factors and effectiveness of preventive measures against influenza in the community

Please cite this paper as: Castilla et al. (2013) Risk factors and effectiveness of preventive measures against influenza in the community. Influenza and Other Respiratory Viruses 7(2) 177–183. Background  The role of different risk exposures and preventive measures against influenza has not been well established. Objective  The aim of this study was to evaluate risk factors and measures to prevent influenza infection in the community. Methods  We conducted a multicenter case–control study. Cases were 481 outpatients aged 18 years or older with laboratory-confirmed influenza A(H1N1)09 in the 2009–2010 season in Spain. A control was selected for each case from outpatients from the same area …

Whole genome sequencing analysis of intrapatient microevolution in Mycobacterium tuberculosis: potential impact on the inference of tuberculosis transmission.

Background. It has been accepted that the infection by Mycobacterium tuberculosis (M. tuberculosis) can be more heterogeneous than considered. The emergence of clonal variants caused by microevolution events leading to population heterogeneity is a phenomenon largely unexplored. Until now, we could only superficially analyze this phenomenon by standard fingerprinting (RFLP and VNTR).Methods. In this study we applied whole genome sequencing for a more in-depth analysis of the scale of microevolution both at the intrapatient and interpatient scenarios.Results. We found that the amount of variation accumulated within a patient can be as high as that observed between patients along a chain of t…

Phylogenetic analysis of environmental Legionella pneumophila isolates from an endemic area (Alcoy, Spain).

Environmental surveillance of Legionella pneumophila is a key component of the control measures established in urban settlements to ensure water safety and quality, with the aim of minimizing and limiting opportunistic infections in humans. In this work, we present results on the detection and genetic characterization of these bacteria in the outbreak-recurrent region of Alcoy (Comunidad Valenciana, Spain) using water and biofilm samples. We were particularly interested in studying the presence and distribution of L. pneumophila in the absence of outbreak or sporadic cases of legionellosis and in comparing the efficacy of culturing from water samples with a biofilm-based detection procedure…

Influenza vaccine effectiveness in preventing outpatient, inpatient, and severe cases of laboratory-confirmed influenza.

Background. In most seasons, the influenza vaccine is effective in preventing influenza, but it is not clear whether it is equally effective in preventing mild and severe cases. We designed a case-control study to compare the effectiveness of the influenza vaccine in preventing outpatient, inpatient, and severe or fatal cases of laboratory-confirmed influenza. Methods. Hospitalized patients (n = 691) with laboratory-confirmed influenza in the 2010–2011 season recruited in 29 Spanish hospitals were individually matched by age, admission/visit date, and province with an outpatient with laboratory-confirmed influenza and an outpatient control. Severe cases were considered those patients admitt…

Genotyping of a nosocomial outbreak of pandemic influenza A/H1N1 2009

Background: Epidemiological surveys have revealed outbreaks of pandemic influenza A (H1N1) 2009 in several different contexts. Molecular characterization of the influenza virus could help to provide a more accurate description of these outbreaks. Objective: To genotype pandemic influenza A (H1N1) 2009 isolates from an epidemiologically defined nosocomial outbreak. Study design: We sequenced the neuraminidase (NA) and hemagglutinin (HA) influenza A (H1N1) 2009 genes from ten HIV-positive patients involved in an epidemiologically defined outbreak in the Clinical Microbiology and Infectious Diseases (CMID) Department. Sequences were aligned to search for specific genetic features of the involv…

The effect of periodic bottlenecks on the competitive ability of Drosophila pseudoobscura lines.

Competition experiments between several Drosophila pseudoobscura strains that were previously subjected to periodic bottlenecks of different sizes and D. willistoni have been carried out. Contrary to previous results with these two species, where stable coexistence was detected, populations of D. pseudoobscura displaced D. willistoni in a few generations. By using a relative fitness measure, the control lines (that had not gone through bottlenecks) outcompeted D. willistoni faster than bottlenecked lines. One of these, corresponding to the minimum possible bottleneck size of one pair, also shows significantly lower relative fitness than the other strains. These results are discussed in rela…

Unraveling the evolutionary history of the phosphoryl-transfer chain of the phosphoenolpyruvate:phosphotransferase system through phylogenetic analyses and genome context

[Background] The phosphoenolpyruvate phosphotransferase system (PTS) plays a major role in sugar transport and in the regulation of essential physiological processes in many bacteria. The PTS couples solute transport to its phosphorylation at the expense of phosphoenolpyruvate (PEP) and it consists of general cytoplasmic phosphoryl transfer proteins and specific enzyme II complexes which catalyze the uptake and phosphorylation of solutes. Previous studies have suggested that the evolution of the constituents of the enzyme II complexes has been driven largely by horizontal gene transfer whereas vertical inheritance has been prevalent in the general phosphoryl transfer proteins in some bacter…

Comprehensive Screening for Naturally Occurring Hepatitis C Virus Resistance to Direct-Acting Antivirals in the NS3, NS5A, and NS5B Genes in Worldwide Isolates of Viral Genotypes 1 to 6.

ABSTRACTThere is no comprehensive study available on the natural hepatitis C virus (HCV) polymorphism in sites associated with resistance including all viral genotypes which may present variable susceptibilities to particular direct-acting antivirals (DAAs). This study aimed to analyze the frequencies, genetic barriers, and evolutionary histories of naturally occurring resistance-associated variants (RAVs) in the six main HCV genotypes. A comprehensive analysis of up to 103 RAVs was performed in 2,901, 2,216, and 1,344 HCV isolates for the NS3, NS5A, and NS5B genes, respectively. We report significant intergenotypic differences in the frequencies of natural RAVs for these three HCV genes. I…

Corrigendum: Phylogeny of Vibrio vulnificus From the Analysis of the Core-Genome: Implications for Intra-Species Taxonomy

Effectiveness of pandemic and seasonal influenza vaccines in preventing pandemic influenza-associated hospitalization.

Vaccines are leading pharmacological measures for limiting the impact of pandemic influenza in the community. The objective of this study was to investigate the effectiveness of influenza (pandemic and seasonal) vaccines in preventing pandemic influenza-associated hospitalization. We conducted a multicenter matched case-control study in 36 Spanish hospitals. Patients hospitalized with confirmed pandemic influenza between November 2009 and February 2010 and two hospitalized controls per case, matched according to age, date of hospitalization and province of residence, were selected. Multivariate analysis was performed using conditional logistic regression. Subjects were considered vaccinated…

MOESM1 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 1. Data analysis and methods used in the reanalysis of Chinese Treponema pallidum samples.

Genetic variability in environmental isolates of Legionella pneumophila from Comunidad Valenciana (Spain).

Summary Legionella pneumophila is associated to recurrent outbreaks in several Comunidad Valenciana (Spain) localities, especially in Alcoi, where social and climatic conditions seem to provide an excellent environment for bacterial growth. We have analysed the nucleotide sequences of three loci from 25 environmental isolates from Alcoi and nearby locations sampled over 3 years. The analysis of these isolates has revealed a substan- tial level of genetic variation, with consistent patterns of variability across loci, and comparable to that found in a large, European-wide sampling of clinical isolates. Among the tree loci studied, fliC showed the highest level of nucleotide diversity. The an…

Antibiotics as selectors and accelerators of diversity in the mechanisms of resistance: from the resistome to genetic plasticity in the β-lactamases world

Antibiotics and antibiotic resistance determinants, natural molecules closely related to bacterial physiology and consistent with an ancient origin, are not only present in antibiotic-producing bacteria. Throughput sequencing technologies have revealed an unexpected reservoir of antibiotic resistance in the environment. These data suggest that co-evolution between antibiotic and antibiotic resistance genes has occurred since the beginning of time. This evolutionary race has probably been slow because of highly regulated processes and low antibiotic concentrations. Therefore to understand this global problem, a new variable must be introduced, that the antibiotic resistance is a natural even…

Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

14 páginas, 5 figuras, 2 tablas.

Background Genetic variability in viral populations is usually estimated by means of polymerase chain reaction (PCR) based methods in which the relative abundance of each amplicon is assumed to be proportional to the frequency of the corresponding template in the initial sample. Although bias in template-to-product ratios has been described before, its relevance in describing viral genetic variability at the intrapatient level has not been fully assessed yet.

Expansion of the CRF19_cpx Variant in Spain

Abstract Background HIV-1 CRF19_cpx, is a recombinant variant found almost exclusively in Cuba and recently associated to a faster AIDS onset. Infection with this variant leads to higher viral loads and levels of RANTES and CXCR4 co-receptor use. Objectives The goal of this study was to assess the presence of CRF19_cpx in the Spanish province of Valencia, given its high pathogenicity. Study design 1294 HIV-1 protease-reverse transcriptase (PR/RT) sequences were obtained in Valencia (Spain), between 2005 and 2014. After subtyping, the detected CRF19_cpx sequences were aligned with 201 CRF19_cpx and 66 subtype D sequences retrieved from LANL, and subjected to maximum-likelihood phylogenetic a…

Molecular characterization and cytonuclear disequilibria of two Drosophila subobscura mitochondrial haplotypes.

According to restriction site analyses of mitochondrial DNA, Drosophila subobscura shows a polymorphism that consists of two frequent haplotypes that are evenly distributed all over the Old World and several rare haplotypes never present in more than one locality. To ascertain the causes responsible for such distribution, three different mtDNA fragments from haplotypes I and II sampled in a population from Zürich have been partially sequenced. Only three silent nucleotide changes have been detected in the ND5 gene. One of them implies the loss of the HaeIII restriction site, which differentiates haplotype I from haplotype II. On the basis of these results as well as on others involving the…

Complete analysis of the epidemiological scenario around a SARS-CoV-2 reinfection: previous infection events and subsequent transmission

9 páginas, 3 figuras. The data that support the findings of this study (Fastq files) are publicly available. Fastq files above the GISAID thresholds were deposited at GISAID (hCoV-19/Spain/MD-IBV-99007733/2020, hCoV-19/Spain/MD-IBV-99007151/2020, hCoV-19/Spain/MD-IBV-99007734/2020, and hCoV-19/Spain/MDIBV-99007170/2020). All sequences were also deposited at the ENA (European Nucleotide Archive; https:// www.ebi.ac.uk/ena/browser/home) (ERR5698024, ERR5697187, ERR6459974, ERR5698025, and ERR5697254).

In this report we re-examine some recent experiments with digital organisms to test some predictions of quasispecies theory. These experiments revealed that under high mutation rates populations of less fit organisms previously adapted to such high mutation rates were able to outcompete organisms with higher average fitness but adapted to low mutation rates. We have verified that these results do hold in the original conditions and, by extending the set of initial parameters, we have also detected that the critical mutation rate was independent of population size, a result that we have found to be dependent on a different, contingent factor, the initial fitness vector. Furthermore, in all b…

A population genetic study of the endangered plant speciesLimonium dufourii(Plumbaginaceae) based on amplified fragment length polymorphism (AFLP)

Limonium dufourii (Plumbaginaceae) is a triploid species with obligate apomictic reproduction and is endemic to the East Mediterranean coast of Spain, where it is present in only six populations, most of which have a very low number of individuals. Genetic variation and population structure in this species was studied using amplified fragment length polymorphisms (AFLPs) as markers, using the same individuals as in a previous study with random amplified polymorphic DNA (RAPD). Three different primers provided 252 bands of which 51 were polymorphic among the 152 individuals analysed. Those polymorphic bands were able to define 65 different phenotypes, of which all but two were present in onl…

Molecular Surveillance of HIV-1 in Madrid, Spain: a Phylogeographic Analysis ▿

ABSTRACT The molecular epidemiology of HIV-1 is constantly changing, mainly as a result of human migratory flows and the high adaptive ability of the virus. In recent years, Spain has become one of Europe's main destinations for immigrants and one of the western European countries with the highest rates of HIV-positive patients. Using a phylogeographic approach, we have analyzed the relationship between HIV-1 variants detected in immigrant and native populations of the urban area of Madrid. Our project was based on two coincidental facts. First, resistance tests were extended to naïve and newly diagnosed patients, and second, the Spanish government legislated the provision of legal status t…

Whole-genome sequencing for TB source investigations : principles of ethical precision public health

[Background]: Whole-genome sequencing (WGS) of Mycobacterium tuberculosis allows rapid, accurate inferences about the sources, location and timing of transmission. However, in an era of heightened concern for personal privacy and science distrust, such inferences could result in unintended harm and undermine the public's trust.

Gene flow rates in Yugoslavian populations of the smooth newt Triturus vulgaris

Allozymic variation in 22 loci in several Yugoslavian populations of four subspecies of the smooth newt Triturus vulgaris, has been analyzed. The frequency of private alleles and the coefficient of genetic differentiation, FST, give very different indirect estimates of the effective number of migrants per generation, Nm. However, such Nm estimates, in most cases higher than 1, imply that gene flow between populations is large enough as to prevent differentiation by random drift. In the case of T.v. vulgaris, of which sixteen populations amply distributed through Yugoslavia were sampled, there is evidence that frequent extinction and recolonization processes might be responsible for the obse…

Phylogenetic signal and functional categories in Proteobacteria genomes

Abstract Background A comprehensive evolutionary analysis of bacterial genomes implies to identify the hallmark of vertical and non-vertical signals and to discriminate them from the presence of mere phylogenetic noise. In this report we have addressed the impact of factors like the universal distribution of the genes, their essentiality or their functional role in the cell on the inference of vertical signal through phylogenomic methods. Results We have established that supermatrices derived from data sets composed mainly by genes suspected to be essential for bacterial cellular life perform better on the recovery of vertical signal than those composed by widely distributed genes. In addit…

Multiple methods for the identification of polymorphic simple sequence repeats (SSRs) in sorghum [Sorghum bicolor (L.) Moench]

Simple sequence repeats (SSRs), also known as microsatellites, are highly variable DNA sequences that can be used as markers for the genetic analysis of plants. Three approaches were followed for the development of PCR primers for the amplification of DNA fragments containing SSRs from sorghum [Sorghum bicolor (L.) Moench]: a search for sorghum SSRs in public DNA databases; the use of SSR-specific primers developed in the Poaceae species maize (Zea mays L.) and seashore paspalum grass (Paspalum vaginatum Swartz); and the screening of sorghum genomic libraries by hybridization with SSR oligonucleotides. A total of 49 sorghum SSR-specific PCR primer pairs (two designed from GenBank SSR-contai…

Contribution of insertions and deletions to the variability of hepatitis C virus populations

Little is known about the potential effects of insertions and deletions (indels) on the evolutionary dynamics of hepatitis C virus (HCV). In fact, the consequences of indels on antiviral treatment response are a field of investigation completely unexplored. Here, an extensive sequencing project was undertaken by cloning and sequencing serum samples from 25 patients infected with HCV subtype 1a and 48 patients with subtype 1b. For 23 patients, samples obtained after treatment with alpha interferon plus ribavirin were also available. Two genome fragments containing the hypervariable regions in the envelope 2 glycoprotein and the PKR-BD domain in NS5A were sequenced, yielding almost 16 000 seq…

Comparison of clinical and environmental samples of Legionella pneumophila at the nucleotide sequence level

Legionella pneumophila serogroup 1 is the most common etiological agent of legionellosis. We have used clinical and environmental isolates from different sources to compare their genetic variability. We have obtained the nucleotide sequence for six protein-coding loci, included in the SBT scheme for L. pneumophila, and three intergenic regions from 127 samples, 47 of environmental origin and 80 from clinical samples. Levels of genetic variability were found to be higher in the environmental than in the clinical samples, but these did not represent a mere subset of the former. Not a single case of full identity between clinical and environmental isolates was found, which raises the possibili…

On the analysis of viability data: an example with Drosophila.

Larval competition experiments involving two wild type and eight mutant strains of Drosophila melanogaster have been carried out following the substitution procedure proposed by Mather and Caligari (1981). Our main goal has been to compare the competitive abilities of two phenotypically indistinguishable strains (wild and Oregon-R) by means of their responses with eight different mutants. Prior to the analyses of viability data, we have studied the normalizing effect of several transformations in order to determine which was best suited for the analyses. The differences found among the five transformations tested and the untransformed data were not very great. The folded power transformatio…

Using evolutionary tools to refine the new hypervariable region 3 within the envelope 2 protein of hepatitis C virus

Abstract The envelope 2 protein of hepatitis C virus (HCV) presents three hypervariable regions, named HVR1, HVR2 and HVR3, in which the presence of antigenic sites has been described. Genetic variability in these regions may reflect the generation of escape mutants as a consequence of the immune response. Therefore, these regions would tend to accumulate amino acid changes along the infection process, an effect that could be accelerated by antiviral treatments. In this study, we have analyzed the E1–E2 region of 23 HCV patients non-responders to antiviral treatment, 7 of which were infected with subtype 1a, 15 with subtype 1b, and 1 with a new HCV-1 subtype, before and after 6 and/or 12 mo…

A20 Sample preparation for whole-genome next-generation sequencing (NGS) of hepatitis C virus (HCV) routine RNA samples

Abstract Next-generation sequencing (NGS) is a technique that can capture the variability of viral populations in transmission studies. The conventional sample preparation for NGS, based on amplicons, is a potential source of errors, derived from the variable affinity of specific primers for different viral variants and from irregular DNA polymerase efficiency. In this context, we propose a more reliable method for viral whole genome sample preparation, starting from nucleic acids obtained and stored with conventional procedures. Our goal was to obtain complete hepatitis C virus (HCV) genome sequences to subsequently perform extensive phylogenetic analyses. Additionally, we aimed to test th…

Enterovirus Co-infections and Onychomadesis after Hand, Foot, and Mouth Disease, Spain, 2008

Mixed infection of enteroviruses may explain the rare complication of nail shedding. Onychomadesis after HFMD

Gene expression models based on a reference laboratory strain are bad predictors of Mycobacterium tuberculosis complex transcriptional diversity

ABSTRACTSpecies of the Mycobacterium tuberculosis complex (MTBC) kill more people every year than any other infectious disease. As a consequence of its global distribution and parallel evolution with the human host the bacteria is not genetically homogeneous. The observed genetic heterogeneity has relevance at different phenotypic levels, from gene expression to epidemiological dynamics. However current systems biology datasets have focused in the laboratory reference strain H37Rv. By using large expression datasets testing the role of almost two hundred transcription factors, we have constructed computational models to grab the expression dynamics of Mycobacterium tuberculosis H37Rv genes.…

Larval competition in Drosophila melanogaster: frequency-dependence of viability

The application of the overfeeding technique (interruption of the competition during larval development) to the study of larval competition in two-strain cultures of Drosophila melanogaster demonstrates the following points: (1) viability is a function of competition time; (2) viability becomes more frequency-dependent as competition time increases; (3) the dynamics of the “inner” subpopulation (adults that have passed all their development in a crowded condition) and “outer” subpopulation (adults coming from larvae recovered by interruption of competition) vary with time as regards frequency-dependence; and (4) the wild type strain Oregon is the active agent in competition with the strain …

Generalized Linear Model (GLM) framework for the association of host variables and viral strains with liver fibrosis in HCV/HIV coinfected patients

Chronic hepatitis C virus (HCV) infection is the main cause of advanced and end-stage liver disease world-wide, and an important factor of morbidity and mortality in Human Immunodeficiency virus-1 (HIV-1) co-infected individuals. Whereas the genetic variability of HCV has been studied extensively in monoinfected patients, comprehensive analyses of both patient and virus characteristics are still scarce in HCV/HIV co-infection. In order to find correlates for liver damage, we sought to analyze demographic, epidemiological and clinical features of HCV/HIV co-infected patients along with the genetic makeup of HCV (viral subtypes and lineage studied by nucleotide sequencing and phylogenetic ana…

L’evolució en els tribunals: aplicacions forenses de les filogènies moleculars

En les dues ultimes decades s’ha generalitzat l’us de proves genetiques en els tribunals, la qual cosa ha permes identificar criminals a partir de restes biologiques, determinar paternitats o identificar cadavers. Menys conegudes son les proves pericials basades en l’us de filogenies moleculars en que s’estudia l’ancestralitat comuna d’organismes, normalment virus o bacteris, per establir com s’associen a una font d’infeccio. Des del cas del dentista de Florida, que va infectar amb el VIH alguns dels seus pacients, fins al mes proxim de l’anestesista Juan Maeso, que va transmetre el VHC a vora 300 pacients, la teoria evolutiva te un paper essencial en aquestes proves. En aquest article s’ex…

Polyphyletic Origin of Vibrio vulnificus Biotype 2 as Revealed by Sequence-Based Analysis ▿ †

ABSTRACT A sequence-based analysis of seven housekeeping and virulence-related genes shows that the species Vibrio vulnificus is subdivided into three phylogenetic lineages that do not correspond with the biotypes and that biotype 2 is polyphyletic. These results support the reclassification of biotype 2 as a pathovar that would group the strains with pathogenic potential to develop vibriosis in fish.

Predictive factors of severe multilobar pneumonia and shock in patients with influenza

PurposeTo identify risk factors present at admission in adult patients hospitalised due to influenza virus infection during the 2009/10 and 2010/11 seasons—including whether infection was from pandemic or seasonal influenza A infections—that were associated with the likelihood of developing severe pneumonia with multilobar involvement and shock.MethodsProspective cohort study. Patients hospitalised due to influenza virus infection were recruited. We collected information on sociodemographic characteristics, pre-existing medical conditions, vaccinations, toxic habits, previous medications, exposure to social environments, and EuroQoL-5D (EQ-5D). Severe pneumonia with multilobar involvement a…

The first wave of the Spanish COVID-19 epidemic was associated with early introductions and fast spread of a dominating genetic variant

The COVID-19 pandemic has shaken the world since the beginning of 2020. Spain is among the European countries with the highest incidence of the disease during the first pandemic wave. We established a multidisciplinar consortium to monitor and study the evolution of the epidemic, with the aim of contributing to decision making and stopping rapid spreading across the country. We present the results for 2170 sequences from the first wave of the SARS-Cov-2 epidemic in Spain and representing 12% of diagnosed cases until 14th March. This effort allows us to document at least 500 initial introductions, between early February-March from multiple international sources. Importantly, we document the …

The substitution rate of HIV-1 subtypes: a genomic approach

Abstract HIV-1M causes most infections in the AIDS pandemic. Its genetic diversity is defined by nine pure subtypes and more than sixty recombinant forms. We have performed a comparative analysis of the evolutionary rate of five pure subtypes (A1, B, C, D, and G) and two circulating recombinant forms (CRF01_AE and CRF02 AG) using data obtained from nearly complete genome coding sequences. Times to the most recent common ancestor (tMRCA) and substitution rates of these HIV genomes, and their genomic partitions, were estimated by Bayesian coalescent analyses. Genomic substitution rate estimates were compared between the HIV-1 datasets analyzed by means of randomization tests. Significant diff…

Evolution of arginine deiminase (ADI) pathway genes

We have analyzed the evolution of the three genes encoding structural enzymes of the arginine deiminase (ADI) pathway, arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) in a wide range of organisms, including Archaea, Bacteria, and Eukarya. This catabolic route was probably present in the last common ancestor to all the domains of life. The results obtained indicate that these genes have undergone a complex evolutionary history, including horizontal transfer events, duplications, and losses. Therefore, these genes are not adequate to infer organismal relationships at deep branching levels, but they provide an insight into how catabolic genes evolved and …

Comparative analysis of variation and selection in the HCV genome

AbstractGenotype 1 of the hepatitis C virus (HCV) is the most prevalent of the variants of this virus. Its two main subtypes, HCV-1a and HCV-1b, are associated to differences in epidemic features and risk groups, despite sharing similar features in most biological properties. We have analyzed the impact of positive selection on the evolution of these variants using complete genome coding regions, and compared the levels of genetic variability and the distribution of positively selected sites. We have also compared the distributions of positively selected and conserved sites considering different factors such as RNA secondary structure, the presence of different epitopes (antibody, CD4 and C…

Phylogeography and genetic variation of Triatoma dimidiata, the main Chagas disease vector in Central America, and its position within the genus Triatoma.

Background Among Chagas disease triatomine vectors, the largest genus, Triatoma, includes species of high public health interest. Triatoma dimidiata, the main vector throughout Central America and up to Ecuador, presents extensive phenotypic, genotypic, and behavioral diversity in sylvatic, peridomestic and domestic habitats, and non-domiciliated populations acting as reinfestation sources. DNA sequence analyses, phylogenetic reconstruction methods, and genetic variation approaches are combined to investigate the haplotype profiling, genetic polymorphism, phylogeography, and evolutionary trends of T. dimidiata and its closest relatives within Triatoma. This is the largest interpopulational …

The molecular epidemiology of HIV-1 in the Comunidad Valenciana (Spain): analysis of transmission clusters

AbstractHIV infections are still a very serious concern for public heath worldwide. We have applied molecular evolution methods to study the HIV-1 epidemics in the Comunidad Valenciana (CV, Spain) from a public health surveillance perspective. For this, we analysed 1804 HIV-1 sequences comprising protease and reverse transcriptase (PR/RT) coding regions, sampled between 2004 and 2014. These sequences were subtyped and subjected to phylogenetic analyses in order to detect transmission clusters. In addition, univariate and multinomial comparisons were performed to detect epidemiological differences between HIV-1 subtypes, and risk groups. The HIV epidemic in the CV is dominated by subtype B i…

Effect of Ribavirin on the Mutation Rate and Spectrum of Hepatitis C Virus In Vivo

ABSTRACTTheir extremely error-prone replication makes RNA viruses targets for lethal mutagenesis. In the case of hepatitis C virus (HCV), the standard treatment includes ribavirin, a base analog with an in vitro mutagenic effect, but the in vivo mode of action of ribavirin remains poorly understood. Here, we test the mutagenic effects of ribavirin plus interferon treatment in vivo using a new method to estimate mutation rates based on the analysis of nonsense mutations. We apply this methodology to a large HCV sequence database containing over 15,000 reverse transcription-PCR molecular clone sequences from 74 patients infected with HCV. We obtained an estimate of the spontaneous mutation ra…

Ultradeep Sequencing Analysis of Population Dynamics of Virus Escape Mutants in RNAi-Mediated Resistant Plants

Plant artificial micro-RNAs (amiRs) have been engineered to target viral genomes and induce their degradation. However, the exceptional evolutionary plasticity of RNA viruses threatens the durability of the resistance conferred by these amiRs. It has recently been shown that viral populations not experiencing strong selective pressure from an antiviral amiR may already contain enough genetic variability in the target sequence to escape plant resistance in an almost deterministic manner. Furthermore, it has also been shown that viral populations exposed to subinhibitory concentrations of the antiviral amiR speed up this process. In this article, we have characterized the molecular evolutiona…

The evolutionary origin of Xanthomonadales genomes and the nature of the horizontal gene transfer process.

Determining the influence of horizontal gene transfer (HGT) on phylogenomic analyses and the retrieval of a tree of life is relevant for our understanding of microbial genome evolution. It is particularly difficult to differentiate between phylogenetic incongruence due to noise and that resulting from HGT. We have performed a large-scale, detailed evolutionary analysis of the different phylogenetic signals present in the genomes of Xanthomonadales, a group of Proteobacteria. We show that the presence of phylogenetic noise is not an obstacle to infer past and present HGTs during their evolution. The scenario derived from this analysis and other recently published reports reflect the confound…

Population Genomics of Human Viruses

Viruses, and a few RNA viruses in particular, represent one of the greatest threats for human health. High mutation rates, large population sizes, and short generation times contribute to their typically fast evolutionary rates. However, many additional processes operate on their genomes, often in opposite directions, driving their evolution and allowing them to adapt to diverse host populations and antiviral drugs. Until recently, the high levels of genetic variation of most viruses have been explored only at a few genes or genome regions. The recent advent and increasing affordability of next-generation sequencing techniques have allowed obtaining complete genome sequences of large number…

Transmission dynamics of HIV-1 subtype B in the Basque Country, Spain

This work was aimed to study the HIV-1 subtype B epidemics in the Basque Country, Spain. 1727 HIV-1 subtype B sequences comprising protease and reverse transcriptase (PR/RT) coding regions, sampled between 2001 and 2008, were analyzed. 156 transmission clusters were detected by means of phylogenetic analyses. Most of them comprised less than 4 individuals and, in total, they included 441 patients. Six clusters comprised 10 or more patients and were further analyzed in order to study their origin and diversification. Four clusters included men who had unprotected homosexual sex (MSM), one group was formed by intravenous drug users (IDUs), and another included both IDUs and people infected th…

Evolution of fitness in experimental populations of vesicular stomatitis virus

Abstract The evolution of fitness in experimental clonal populations of vesicular stomatitis virus (VSV) has been compared under different genetic (fitness of initial clone) and demographic (population dynamics) regimes. In spite of the high genetic heterogeneity among replicates within experiments, there is a clear effect of population dynamics on the evolution of fitness. Those populations that went through strong periodic bottlenecks showed a decreased fitness in competition experiments with wild type. Conversely, mutant populations that were transferred under the dynamics of continuous population expansions increased their fitness when compared with the same wild type. The magnitude of …

The widespread presence of a family of fish virulence plasmids in Vibrio vulnificus stresses its relevance as a zoonotic pathogen linked to fish farms

Vibrio vulnificus is a pathogen of public health concern that causes either primary septicemia after ingestion of raw shellfish or secondary septicemia after wound exposure to seawater. In consequence, shellfish and seawater are considered its main reservoirs. However, there is one aspect of its biology that is systematically overlooked: its association with fish in its natural environment. This association led in 1975 to the emergence of a zoonotic clade within phylogenetic lineage 2 following successive outbreaks of vibriosis in farmed eels. Although this clade is now worldwide distributed, no new zoonotic clades were subsequently reported. In this work, we have performed phylogenetic, ge…

The widespread presence of a family of fish virulence plasmids in Vibrio vulnificus stresses its relevance as a zoonotic pathogen linked to fish farms

Vibrio vulnificus is a pathogen of public health concern that causes either primary septicemia after ingestion of raw shellfish or secondary septicemia after wound exposure to seawater. In consequence, shellfish and seawater are considered its main reservoirs. However, there is one aspect of its biology that is systematically overlooked: its association with fish in its natural environment. This association led in 1975 to the emergence of a zoonotic clade within phylogenetic lineage 2 following successive outbreaks of vibriosis in farmed eels. Although this clade is now worldwide distributed, no new zoonotic clades were subsequently reported. In this work, we have performed phylogenetic, ge…

MOESM4 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 4. A Genome coverage statistics—number of non-covered bases for individual Chinese strains. SS14 genome (CP004011.1) [6] was used as a reference for mapping; coordinates according to the CP004011.1. The list includes all positions without any coverage by mapped reads. B Genome covearge statistics—number of zero covered bases for individual Chinese strains. Nichols genome (CP004010.2) [6] was used as a reference for mapping; coordinates according to the CP004010.2. The list includes all positions without any coverage by mapped reads.

MOESM9 of Reanalysis of Chinese Treponema pallidum samples: all Chinese samples cluster with SS14-like group of syphilis-causing treponemes

Additional file 9. Genomic SNVs used for phylogenetic analysis. List of SNVs used for construction of phylogenetic trees. Only SNVs detected in all analyzed genomes (i.e., positions with the “N” base in any of the compared genomes were not considered) were used in the analysis. Genes tp0433 (arp), tp0470, and tp0897 (tprK) were excluded from analyses. Altogether, 2444 unique SNV positions were identified when the TPE Fribourg-Blanc genome sequence was used as an outgroup. Coordinates (positions) and gene annotations according to the SS14 genome (CP04011.1); “NA” = not annotated (IGR, intergenic region); “.” = deletion.