Project description:A microarray was developed to screen rodent samples for pathogens of zoonotic importance In the work described here, a homologue to Yersinia pestis was found in rodent samples after screening with the microarray A number of rodent samples from the UK and Canada were identified as carrying a homologue to a Yersinia pestis gene
Project description:Yersinia pestis (Y. pestis) is the etiologic agent of the plague, an endemic zoonotic disease of critical clinical and historic importance. The species belongs to a genus comprising eleven members, three of which are human pathogens. Y. pestis and its closest extant relative, Yersinia pseudotuberculosis, are very similar in many respects, yet there is a distinct dichotomy between these species in terms of pathogenicity. Y. pseudotuberculosis produces a relatively benign food- or water-borne gastroenteritis with rare cases of potentially fatal bacteremia. In contrast, the characteristics of high infectivity and high mortality have made Y. pestis a pathogen of historic importance with devastating effects on the human populace over the course of three major pandemics. These qualities coupled with the emergence of multi-drug resistant variants make Y. pestis an ideal candidate for use as a bioterrorism agent. Consequentially, evolutionary biology of this organism has become a priority in the counter-terrorism research effort. The flow of genetic information within the Y. pseudotuberculosis/Y. pestis group motivated us to identify novel genes for the purpose of creating a pan-genome species DNA microarray to better understand the phylogenomic relationships among its members. Based on the sequence information be generated from the novel gene discovery project conducted at the PFGRC as well as other publicly available sources regarding Yersinia spp. genome sequences, we designed a species microarray which represents the hitherto known genetic repertoire of this taxonomic group. In order to create a species microarray that represents novel genes or genes with significant sequence variation, the ArrayOligoSelector software (http://arrayoligosel.sourceforge.net/) was used to design a 70-mer oligonucleotide for each of the annotated ORFs or partial ORFs. A detailed description of the 70-mer oligo design process and filters developed by the PFGRC can be found on the PFGRC web site at (http://pfgrc.tigr.org/presentations/seminars/oligo_design_final.pdf).
Project description:Following a pacemaker implantation, a 75-years-old patient suffered from five successive bacteremia episodes between in 1999 and 2013, during which five bacterial strains were isolated. Phenotypic and whole-genome sequencing analysis of four isolates identified the strains as Yersinia enterocolitica bioserotype 4/O:3. Phylogenetic reconstruction showed that the patient was chronically infected by the same strain, which evolved within the host during 14 years. Single-nucleotide polymorphhism (SNP) analysis indicates that the last two isolates which displayed severe growth defects in vitro and acquired resistance to quinolones, evolved in parallel and formed two independent lineages within the host. Pan-genome analysis and genome comparison showed that their common evolution was characterized by 41 small insertion/deletion events and loss of three large DNA fragments. These mutations, which may account for the observed growth defect and also for the appearance of vegetations on the pacemaker, support antibiotics tolerance. Quinolone resistance was acquired through a so far undescribed deletion in the gyrA gene. 140 genes containing mutations vertically acquired from a common ancestor were also identified in the two lineages. A phylogenetic analysis by maximum likelihood identified two genes presenting a positive selection signal, suggesting that these mutations provided a survival advantage to bacteria during chronic infection. This is the first report allowing identification of genetic changes associated to within-host adaptation of a pathogenic Yersinia species.
Project description:Enteropathogenic Yersinia enterocolitica and Yersinia pseudotuberculosis share many traits in terms of infections they cause, but their epidemiology and ecology seem to differ in many ways. Pigs are the only known reservoir for Y. enterocolitica 4/O:3 strains while Y. pseudotuberculosis strains have been isolated from variety of sources including fresh vegetables and wild animals. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three Yersinia enterocolitica and four Yersinia pseudotuberculosis genomes was conducted to shed light on genomic differences between the enteropathogenic Yersinia. In total 99 strains isolated from various sources were hybridized and analyzed.