Enteropathogenic yersinia spp.

Abstract

Yersinia enterocolitica and Yersinia pseudotuberculosis can cause enteric yersiniosis among humans and animals. The infection is typically acquired through contaminated food but it can also be transmitted directly through human or animal contact. Common symptoms are diarrhoea, abdominal pain and fever but sometimes sequelae as joint pain and skin rash occur. The severity of the infection depends on the age and immunity of the infected person, the virulence of the strain and the infection dose. Y. enterocolitica and Y. pseudotuberculosis differ clearly from each other both pheno and genotypically. Y. enterocolitica species consists of a very heterogeneous group of bacteria and not all Y. enterocolitica strains are pathogenic. Y. pseudotuberculosis strains show little variation in biochemical reactions and they ar e all considered to be pathogenic. Both plasmid and chromosomal encoded virulence factors are needed for Yersinia pathogenicity and all pathogenic strains carry a virulence plasmid which essential for the bacteria to multiply and disseminate in the host. Yersinia strains can grow at low temperatures and under both aerobic and anaerobic conditions but they are heat sensitive. The isolation and identification of enteropathogenic Yersinia is difficult and time consuming, especially when food and environmental samples are studied. More accurate methods should be designed for isolation and identification of Yersinia spp. and more information is needed about transmission routes and sources of enteropathogenic Yersinia strains.