Yersinia enterocolitica : Survival of a Pathogenic Strain on Milk Containers.

A strain of Yersinia enterocolitica isolated from a patient in a milk-associated yersiniosis outbreak in Tennessee, Mississippi and Arkansas in the summer of 1982 was used to contaminate the exterior of refrigerated milk containers. The bacteria survived on the containers for as long as 21 d, as shown by recovery on MacConkey agar plates or in veal infusion broth. Y.

Pathogenicity of Yersinia enterocolitica Demonstrated in the Suckling Mouse.

An experimental suckling mouse intraperitoneal injection test was compared with four plasmid-associated tests (adult mouse peroral exposure, adult mouse intraperitoneal injection, auto-agglutination and plasmid detection by gel electrophoresis) to measure Yersinia enterocolitica pathogenicity. Of eight Vwa plasmid-harboring strains (O:3; O:4,32; O:5,27; O:8; O:9; O:13; O:21; and O:Tacoma) and one isogenic plasmidless strain (O:8), all Vwa plasmid-harboring strains gave identical results in all tests except the two adult mouse tests. In studies of 35 clinical strains of Y.

Detection and enumeration of virulent Yersinia enterocolitica in food by DNA colony hybridization.

A portion of a 44-megadalton plasmid found in Yersinia enterocolitica 8081 was used as a genetic probe to differentiate virulent and nonvirulent strains of the species. A DNA colony hybridization technique was employed. Three BamHI restriction endonuclease fragments labeled with 32P by nick translation were hybridized to lysed colonies of pure cultures, mixtures of virulent and nonvirulent cells, and portions of a food sample artificially contaminated with virulent Y.

Evaluation of virulence factor testing and characteristics of pathogenicity in Yersinia enterocolitica.

The virulence of 10 strains of Yersinia enterocolitica containing 42- to 44-megadalton plasmids (serogroups O:3; O:4,32; O:8; O:9; O:13,7; and O:21) was compared in mice and guinea pigs. Adult mice were more responsive than guinea pigs to the Sereny-like conjunctivitis test. In tests on suckling mice, all Yersinia strains harboring plasmids were lethal, whereas all strains without plasmids were nonlethal.