Detection of Yersinia Pestis by Comparison of Virulence Plasmid (pyv/pcd)-associated Phenotypes in Yersinia Species*

Consumption of meat contaminated with Yersinia pestis can cause oropharyngeal plague in humans. Existing microbiological media designed for selective detection of Y. pestis in food are not satisfactory for that purpose. Expression of genetic determinants in Yersinia species including low calcium response (Lcr), colony size, crystal violet (CV) binding, Congo red (CR) uptake, autoagglutination (AA) and hydrophobicity (HP) were compared. Lcr and CV binding were detectable within 24 h at 37C in Yersinia enterocolitica and Yersinia pseudotuberculosis but at 48 h in Y. pestis. Colony size, AA, and HP characteristics were expressed in Y. pseudotuberculosis and Y. enterocolitica, but not in Y. pestis. CR uptake in Y. pestis was demonstrated only on calcium-deficient CR-magnesium oxalate (CR-MOX) tryptic soy agar but was expressed on both CR-MOX and low-calcium agarose medium forY. pseudotuberculosis and Y. enterocolitica. CR-uptake phenotype by Y. pestis can be used for the detection of this pathogen in foods. PRACTICAL APPLICATIONS Yersinia pestis, Yersinia enterocolitica and Yersinia pseudotuberculosis can cause diverse human diseases. Y. enterocolitica and Y. pseudotuberculosis * Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 3 Corresponding author. TEL: 215-233-6521; FAX: 215-836-6920; EMAIL: saumya.bhaduri@