Search results for "molecular epidemiology"
showing 10 items of 142 documents
Natural Hosts and Genetic Diversity of the Emerging Tomato Leaf Curl New Delhi Virus in Spain
2019
Knowledge about the host range and genetic structure of emerging plant viruses provides insights into fundamental ecological and evolutionary processes, and from an applied perspective, facilitates the design and implementation of sustainable disease control measures. Tomato leaf curl New Delhi virus (ToLCNDV) is an emerging whitefly transmitted begomovirus that is rapidly spreading and inciting economically important diseases in cucurbit crops of the Mediterranean basin. Genetic characterization of the ToLCNDV Mediterranean populations has shown that they are monophyletic in cucurbit plants. However, the extent to which other alternative (cultivated and wild) hosts may affect ToLCNDV genet…
Data mining from a 27-years rotavirus surveillance in Palermo, Italy.
2014
Uninterrupted surveillance conducted in Palermo, Sicily, for 27 years (1985–2012) detected rotavirus infection in 32.7% of 6522 children <5 years of age, hospitalised at the “G. Di Cristina” Children’s Hospital of Palermo. Increased rotavirus activity usually occurred from the beginning of winter to mid-spring. G1P[8] rotaviruses were the prevalent strains in most of the years and were only occasionally overcome by G9P[8], G4P[8] or G2P[4]. The circulation of non-G1P[8] strains was discontinuous and fluctuating. Phylogenetic analyses revealed an heterogeneous population of viruses within each genotype, with different lineages and sublineages emerging over the time. Amino acid substitutions …
Comparison of clinical and environmental samples of Legionella pneumophila at the nucleotide sequence level
2009
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…
GyrA sequence-based typing of Legionella.
2000
Comparative sequence analysis of a 423-bp segment of the gyrA gene including a region homologous to the quinolone resistance-determining region (QRDR) of other species was evaluated as a novel typing method for Legionella strains. The study was performed with 29 reference strains representing 11 different Legionella species, with various serogroups, and with 13 clinical isolates of L. pneumophila. Pulsed-field gel electrophoresis and serotyping were employed for comparison of the clinical isolates. QRDR sequencing proved to be a highly discriminative tool for typing Legionellae, and permitted identification of species, serogroups and even different strains within serogroup 1. None of the is…
Characterization of Listeria monocytogenes isolates from human listeriosis cases in Italy.
2009
ABSTRACT The objective of this study was to characterize by serotyping, pulsed-field gel electrophoresis (PFGE), and PCR amplification of virulence genes and markers of epidemic clones I, II, and III (ECI, ECII, and ECIII) 54 human isolates from apparently sporadic cases of infection occurring in the Lombardy region and in the province of Florence, Tuscany, Italy, in the years 1996 to 2007. Listeria monocytogenes isolates were provided by the clinical microbiology laboratories of the Lombardy region and the “Careggi” Hospital of Florence, Tuscany, Italy. Serotyping, PFGE after digestion with the AscI and ApaI enzymes, and PCR amplification for the inlA , inlC , and inlJ genes and ECI, ECII,…
Multiclonal emergence of carbapenem-resistant Klebsiella pneumoniae in Tuscany, Italy
2010
Surveillance of human astrovirus circulation in Italy 2002-2005: emergence of lineage 2c strains.
2010
AbstractBy screening faecal samples collected over four consecutive years (2002-2005) from hospitalized children with diarrhoea in Palermo, Italy, astroviruses (HAstVs) were detected in 3.95% of the patients. The predominant type circulating was HAstV-1 but, in 2002, only HAstV-2 and -4 were identified. Interestingly, the HAstVs-2 detected appeared to be consistently different in 5′ end of their open reading frame 2 from the previously described subtypes. These novel type 2 strains were included in a new 2c lineage based on the phylogenetic analysis and the presence of nine peculiar substitutions.
Molecular characterization of Italian Candida parapsilosis isolates reveals the cryptic presence of the newly described species Candida orthopsilosis…
2012
The authors report the molecular characterization of Candida parapsilosis isolates recovered from the blood and venous central catheter tips of patients admitted to different care units of the Polyclinic Hospital, University of Messina, Italy. Among 97 presumed C. parapsilosis isolates examined, 94 were identified as C. parapsilosis sensu stricto and the remaining 3 isolates were found to belong to the cryptic species Candida orthopsilosis which was recovered only from blood cultures of neonates (<30 days old) born prematurely. No C. metapsilosis was found in this study. This study emphasizes the role of C. parapsilosis as an important nosocomial pathogen, and it also describes, for the fir…
Systematics of Mepraia (Hemiptera-Reduviidae): cytogenetic and molecular variation.
2009
The haematophagous insects of the subfamily Triatominae (Hemiptera-Reduviidae) have great epidemiological importance as vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Mepraia was originally described as a monotypic genus comprised of Mepraia spinolai, distributed along coastal areas of northern Chile (from Region I to the Metropolitan Region). Recently, some M. spinolai populations have been ranked as a new species named Mepraia gajardoi. Several populations along the distribution range of the genus were sampled, and genetic differentiation was studied based upon the analysis of three molecular markers: cytogenetics (karyotype and chromosome behaviour during meiosis us…