Subdivision of 137 isolates of Yersinia enterocolitica O3 into eight phagovars has been achieved. Some geographical differences were found in the sources of these phagovars and also of two biovars.

Yersinia enterocolitica is an important foodborne pathogen, and pigs are recognized as a major reservoir and potential source of pathogenic strains to humans. A total of 172 Y. enterocolitica recovered from conventional and antimicrobial-free pig production systems from different geographic regions (North Carolina, Ohio, Michigan, Wisconsin, and Iowa) were investigated to determine their pathog...

Yersinia enterocolitica and Yersinia pseudotuberculosis are current sources of pathogenic strains in humans and animals. Yersiniae infections occur throughout the world, but are most prevalent in regions with moderate and subtropical climates. In Australia, Central Europe and North America, cases of human infections with Yersinia enterocolitica now rank in third place. The food-processing indus...

Virulent (plasmid-associated) strains of Yersinia enterocolitica grown on RPMI 1640 agar (RPMI-1640 medium [Flow Laboratories] with 40 mM HEPES and 1.5% [wt/vol] purified agar [Difco]) dissociated into small and large colonies. The autoagglutination test (a marker of virulence) is regularly positive with small colonies and negative with large colonies. Avirulent Y. enterocolitica strains gave o...

Yersinia enterocolitica is known to be associated with gastroenteritis in children and Reiter's syndrome in adults, but it has only rarely been the cause of primary soft tissue infections. A patient with diabetes mellitus developed a calf abscess, from which Y. enterocolitica was isolated in pure culture. Incision, drainage, and intravenous gentamicin therapy resulted in cure.

MacConkey agar modified with Tween 80, and deoxyribonuclease agar modified with Tween 80 plus sorbitol were used in differentiating Yersinia enterocolitica colonies from other lactose-negative bacterial colonies.

The ability of Yersinia to digest polypectate may be of some value in differentiating Y. enterocolitica and Y. pseudotuberculosis from some of the other fermenting gram-negative bacilli, such as Enterobacter agglomerans, with which they can be confused. Pectolytic activity in Yersinia may also have some teleologic or taxonomic significance about which we do not care to speculate.

Of four tested identification systems (API 20E, API Rapid 32 IDE, Micronaut E, and the PCR-based Yersinia enterocolitica Amplification Set), API 20E is still the system of choice for identifying pathogenic Yersinia isolates. It provides the highest sensitivity both at the genus and at the species level and has the best cost-effectiveness correlation.

Of the ∼16 Yersinia species, only Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica are pathogenic to humans (Koornhof et al., 1999; Smego et al., 1999). The zoonotic obligate pathogen Y. pestis is the causal agent of plague, a systemic disease that is usually fatal if left untreated. Free-living Y. enterocolitica and Y. pseudotuberculosis are the agents of yersiniosis, a rarely systemic ...