耶氏菌种中存在致病性和非致病性菌株,故正确判断小肠结肠炎耶氏菌是否致病似有困难。学者们认为该菌的毒力株存在着40～50×10~6道尔顿的质粒。有这种质粒的菌株表现自凝、钙依赖和刚果红吸收的特性。而不具有此质粒但有潜在毒性的小肠结肠炎耶氏菌,通常吡嗪酰胺酶(pyrazinamidase)、水杨甙和七叶树苷试验均为阴性。 Yersinia species exist in the pathogenic and non-pathogenic strains, so correctly determine whether Enterocolitis Yersinia pathogenic similar difficulties. Scholars believe that there are strains of virulent bacteria 40 ~ 50 × 10 ~ 6 Dalton plasmid. Strains with this plasmid exhibit self-condensing, calcium-dependent and Congo red absorption properties. Yersinia enterocolitica without this plasmid but potentially toxic, usually pyrazinamidase, salicin and aescin test were negative.