Novel Virulence-Associated Type II Secretion System Unique to High-PathogenicityYersinia enterocolitica

Abstract

Yersinia enterocolitica strains comprise an important group of bacterial enteropathogens that cause a broad range of gastrointestinal syndromes. Three groups are distinguishable within this bacterial species, namely, the nonpathogenic group (biotype 1A strains), the low-pathogenicity, non-mouse-lethal group (biotypes 2 to 5), and the high-pathogenicity, mouse-lethal group (biotype 1B). To date, the presence of the high-pathogenicity island (HPI), a chromosomal locus that encodes the yersiniabactin system (involved in iron uptake), defines essentially the difference between low-pathogenicity and high-pathogenicity Y. enterocolitica strains, with the low-pathogenicity strains lacking the HPI. Using the powerful tool of representational difference analysis between the nonpathogenic 1A strain, NF-O, and its high-pathogenicity 1B counterpart, WA-314, we have identified a novel type II secretion gene cluster (yts1C-S) occurring exclusively in the high-pathogenicity group. The encoded secreton, designated Yts1 (for Yersinia type II secretion 1) was shown to be important for virulence in mice. A close examination of the almost completed genome sequence of another high-pathogenicity representative, Y. enterocolitica 8081, revealed a second putative type II secretion cluster uniformly distributed among all Y. enterocolitica isolates. This putative species-specific cluster (designated yts2) differed significantly from yts1, while resembling more closely the putative type II cluster present on the genome of Y. pestis. The Yts1 secreton thus appears to have been additionally acquired by the high-pathogenicity assemblage for a virulenceassociated function.The genus Yersinia comprises an important group of bacterial pathogens, with Yersinia enterocolitica, Y. pseudotuberculosis, and Y. pestis representing the species of interest. Y. pestis is the etiologic agent of plague, whereas Y. pseudotuberculosis and Y. enterocolitica are enteropathogens that cause a broad range of gastrointestinal syndromes ranging from acute gastroenteritis to mesenteric lymphadenitis. Central to the pathogenicity of the Yersinia is the presence of a 70-kb pYV virulence plasmid whose products mediate, among other things, the resistance of Yersinia to phagocytosis by polymorphonuclear leukocytes and macrophages (41). In addition, the chromosomally encoded Ail (for attachment invasion loci), Myf (for mucoid Yersinia factor), and Inv (invasin) proteins have been implicated in the virulence of the species to various degrees (3, 38).Two groups have been identified among the Y. enterocolitica strains, which is a focus of the present study: nonpathogenic strains comprising mainly biotype 1A organisms and pathogenic strains carrying the virulence plasmid pYV. The latter group is further subdivided into a low-pathogenicity (LP), nonmouse-lethal group represented by biotypes 2 to 5 and a highpathogenicity (HP), mouse-lethal group exemplified by biotype 1B strains (8). As a mouse virulence determinant, an HP island (HPI) has been identified, which encodes for syn...

Isolation of Yersinia spp. from cases of diarrhoea in Iraqi infants and children

“…This finding is in accordance with many previous studies [1,4]. Also Delor and Cornelis considered that the Yersinia enterotoxin was the cause of diarrhoea in young rabbits and consequently was the major factor involved in the Y. enterocolitica-associated diarrhoea in young children.…”

“…This result is in keeping with Grant et al [9] and Iwobi et al [4] who found that the Peyer's patches ٢٠٠9 ،٢ ‫العدد‬ ‫عرش،‬ ‫اخلامس‬ ‫املجلد‬ ‫العاملية،‬ ‫الصحة‬ ‫منظمة‬ ‫املتوسط،‬ ‫لرشق‬ ‫الصحية‬ ‫املجلة‬ of the intestine were the primary sites for infection with Yersinia. Moreover, enterotoxin production was positive in infant mice with ratios of intestine:total body weight of 0.08 and 0.083.…”

“…Yersiniosis is a clinical condition caused by infection with low-and high-pathogenic species of Yersinia: Y. enterocolitica and Y. pseudotuberculosis [3,4]. The disease is characterized by symptoms of gastroenteritis and/or vomiting with abdominal pain.…”

Prevalence of Very Low Numbers of Potential Pathogenic Isolates of Yersinia enterocolitica and Yersinia intermedia in Traditional Fast Foods of India

“…The native isolates of Y. enterocolitica did exhibit the prevalence of yst and ail genes, which are unique to pathogenic isolates of this species. The native isolates obtained in our study showed the presence of the yts1 gene, which is invariably present only in highly pathogenic group of Y. enterocolitica [25]. Besides, both the native isolates of Y. enterocolitica were also positive for two other important virulence factors such as rovA and myfF (Fig.…”

Synchronous Gene Expression of theYersinia enterocoliticaYsa Type III Secretion System and Its Effectors

“…The two secretion systems have been shown to be required for full virulence in oral infection models (17,18,23). Studies using a mouse model have indicated about a 10-fold increase in the 50% lethal dose of ysa mutants compared to that of wild-type strains, and ysa mutants are defective for colonization of the intestinal tract (17,23).…”