Search results for "Sequence analysi"
showing 10 items of 1351 documents
Molecular Epidemiology and Evolution in an Outbreak of Fulminant Hepatitis B Virus
2006
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…
The role of positive selection in hepatitis C virus
2008
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…
Identification of Three Clinically Relevant Borrelia burgdorferi Sensu Lato Genospecies by PCR-Restriction Fragment Length Polymorphism Analysis of 1…
2004
ABSTRACT We report the results of a study of the prevalences of three clinically relevant Borrelia burgdorferi sensu lato genospecies ( Borrelia burgdorferi sensu stricto, Borrelia afzelii , and Borrelia garinii ) in 1,040 questing Ixodes ticks from all regions of Latvia, where Lyme borreliosis is endemic. The prevalences of Borrelia in Ixodes ricinus and Ixodes persulcatus were 22.6 and 27.9%, respectively. Molecular typing of B. burgdorferi from infected ticks was performed by restriction fragment length polymorphism (RFLP) analysis of PCR-amplified fragments of the 16S-23S ( rrs-rrlA ) rRNA intergenic spacer by using species-specific primers and subsequent sequencing. The dominant Borrel…
Molecular epidemiology of a hepatitis C virus outbreak in a hemodialysis unit.
2005
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…
Human toll-like receptor 4 mutations are associated with susceptibility to invasive meningococcal disease in infancy.
2006
Toll-like receptor 4 (TLR4) is required for efficient recognition of bacterial infections. We investigated an association between 2 TLR4 mutations (Asp 299 Gly and Thr 399 Ile) and meningococcal disease in 197 patients and 214 healthy controls by allele-specific real time polymerase chain reaction and direct sequencing. Although the allele frequency was not higher in the overall patient population, a significantly higher frequency in the 40 patients younger than 12 months of age (P = 0.007) was observed. We conclude that TLR4 mutations represent a risk factor for meningococcal disease in this age group.
A molecular method to assess Phytophthora diversity in environmental samples
2012
Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phy…
SCAR-based real time PCR to identify a biocontrol strain (T1) of Trichoderma atroviride and study its population dynamics in soils.
2006
Strains of Trichoderma spp. are known for their antagonistic properties against plant pathogens, some are already on the market, others are under development. In order to launch a strain on the market its perfect identification at the species and strain levels is needed. The aim of this study is to (i) design a SCAR marker for specific identification of strain T1 of Trichoderma atroviride and (ii) monitor population dynamics of this strain in soil by real time PCR. A primer pair targeting a 141-bp fragment enabled specific detection of this strain without cross detection of autochthonous populations of Trichoderma in several field soils. In two soils, population dynamics assessed by real ti…
Identification of group A porcine rotavirus strains bearing a novel VP4 (P) genotype in Italian swine herds.
2007
ABSTRACT The VP4 gene of a G5 Italian porcine rotavirus strain, 344/04-1, was nontypeable by PCR genotyping. The amino acid sequence of the full-length VP4 protein had low identity (≤76.6%) with the homologous sequences of representative strains of the remaining P genotypes, providing evidence for a novel P genotype.
Molecular characterization of genotype G6 human rotavirus strains detected in Italy from 1986 to 2009.
2011
Group A human rotavirus (HRV) strains with a bovine-like (G6) major outer capsid protein VP7 were first detected in Palermo, Italy, in the late 1980s, and subsequently worldwide. During a 25-year rotavirus surveillance period, additional HRV G6 strains, associated with either a P[9] or P[14] VP4 genotype, have been detected sporadically, but repeatedly, in Palermo. Whether these G6 HRVs were transmitted to humans directly from an animal reservoir or could have circulated at low prevalence in susceptible individuals is uncertain. Upon sequence analyses of the VP7, VP4, VP6, NSP4 and NSP5 gene segments, all the Italian HRV strains displayed a conserved genotype constellation, G6-P[9]/[14]-I2-…
Identification of a multi-reassortant G12P[9] rotavirus with novel VP1, VP2, VP3 and NSP2 genotypes in a child with acute gastroenteritis.
2015
The G12 rotavirus genotype is globally emerging to cause severe gastroenteritis in children. Common G12 rotaviruses have either a Wa-like or DS-1-like genome constellation, while some G12 strains may have unusual genome composition. In this study, we determined the full-genome sequence of a G12P[9] strain (ME848/12) detected in a child hospitalized with acute gastroenteritis in Italy in 2012. Strain ME848/12 showed a complex genetic constellation (G12-P[9]-I17-R12-C12-M11-A12-N12-T7-E6-H2), likely derived from multiple reassortment events, with the VP1, VP2, VP3 and NSP2 genes being established as novel genotypes R12, C12, M11 and N12, respectively. Gathering sequence data on human and anim…