Crown Copyright 1996. This series of fact sheets summarizes current knowledge on organisms which are known or potential pathogens, and which may have the possibility of a waterborne route of infection. Serotypes of Yersinia enterocolitica Strains of Yersinia enterocolitica are found world-wide and cause disease in man and animals. Pathogenicity is associated with carriage of a 70 kb plasmid, non-pathogenic and environmental strains do not harbour this plasmid. Y. enterocolitica is a facultative anaerobe and produces acid from glucose and a variety of carbohydrates.
Some strains produce small amounts of gas from glucose.
All strains are nitrate and catalase positive, hydrolyse urea, decarboxylate ornithine and are methyl red positive. Strains of Y. enterocolitica are negative in tests for oxidase, arginine dihydrolase, lysine decarboxylase, hydrogen sulphide, malonate, phenylalanine deaminase, gelatinase and utilisation of citrate as a sole carbon source. Strains of biotype 1A and 6, are considered to be non-pathogenic whereas the others can be pathogenic. A combination of biotype and serogroup may indicate the likely pathogenicity of an isolate. On nutrient agar colonies are circular, smooth, and low convex with an entire edge.