%0 Journal Article
%T Virulence Plasmid (pYV)-Associated Expression of Phenotypic Virulent Determinants in Pathogenic Yersinia Species: A Convenient Method for Monitoring the Presence of pYV under Culture Conditions and Its Application for Isolation/Detection of Yersinia pestis in Food
%A Saumya Bhaduri
%A James L. Smith
%J Journal of Pathogens
%D 2011
%I Hindawi Publishing Corporation
%R 10.4061/2011/727313
%X In Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica, phenotypic expression of virulence plasmid (pYV: 70-kb)-associated genetic determinants may include low-calcium response (Lcr, pinpoint colony, size = 0.36£¿mm), colony morphology (size = 1.13£¿mm), crystal violet (CV) binding (dark-violet colony), Congo Red (CR) uptake (red pinpoint colony, size = 0.36£¿mm), autoagglutination (AA = cells agglutinate), and hydrophobicity (HP = clumping of cells). Y. pseudotuberculosis is chromosomally closely related to Y. pestis; whereas, Y. enterocolitica is chromosomally more distantly related to Y. pestis and Y. pseudotuberculosis. All three species demonstrate Lcr, CV binding, and CR uptake. The colony morphology/size, AA, and HP characteristics are expressed in both Y. pseudotuberculosis and Y. enterocolitica but not in Y. pestis. Congo red uptake in Y. pestis was demonstrated only on calcium-deficient CR magnesium oxalate tryptic soy agar (CR-MOX), whereas this phenotype was expressed on both CR-MOX and low-calcium agarose media in Y. pseudotuberculosis and Y. enterocolitica. These phenotypes were detectable at 37¡ãCC within 24£¿h in Y. enterocolitica and Y. pseudotuberculosis but did not appear until 48£¿h in Y. pestis due to its slower growth rate at 37¡ãCC. The pYV is unstable (i.e., easily lost under a variety of culture conditions) in all three species but is more unstable in Y. pestis. The specific CR uptake by Y. pestis in CR-MOX and the delayed time interval to express Lcr and CR uptake provide a means to differentiate Y. pestis from Y. enterocolitica and Y. pseudotuberculosis. These differences in pYV expression in Y. pestis can be used for its isolation and detection in food. 1. Introduction The genus Yersinia consists of 11 species, but only Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis are pathogenic to humans. Yersinia pestis is considered to be ancestrally related to Y. pseudotuberculosis; however, Y. pseudotuberculosis behaves phenotypically and clinically like Y. enterocolitica [1]. The three species are quite diverse in the diseases they cause; Y. enterocolitica and Y. pseudotuberculosis induce gastroenteritis when consumed in contaminated food and have been isolated from patients with diarrhea. Yersinia pestis is the agent of bubonic plague and can cause oropharyngeal plague as a result of the consumption of inadequately cooked goat and camel meat or handling of meat from infected animals [2¨C5]. The risk, morbidity, and mortality of contracting plague through the consumption of food deliberately contaminated with Y. pestis are
%U http://www.hindawi.com/journals/jpath/2011/727313/