Evaluation of enzyme immunoassay for the detection of pathogenic Yersinia enterocolitica and Yersinia pseudotuberculosis strains.

To determine the virulence plasmid-harboring strains of Yersinia enterocolitica, we prepared antiserum against plasmid-encoded proteins of Y. enterocolitica serotype O3 and carried out an enzyme immunoassay (EIA) against temperature-inducible released proteins. This serum reacted with proteins released from not only a Y. enterocolitica serotype O3 strain but also Y. enterocolitica serotype O5:27, O8, and O9 and Y. pseudotuberculosis serotype 1b, 2a, 2b, 2c, 3, 4a, 4b, 5a, 5b, 6, 7, and 8 strains, which all harbored plasmids. Plasmid-cured Y. enterocolitica and Y. pseudotuberculosis strains did not react in the EIA, nor did nonpathogenic Y. enterocolitica strains or Y. frederiksenii, Y. intermedia, and Y. kristensenii strains. These observations demonstrated that this EIA was useful for determining whether the isolated Yersinia strains were pathogenic or not.