In vitro invasiveness of Yersinia enterocolitica isolated from children with diarrhea.

The invasiveness of Yersinia enterocolitica isolated from the feces of children with diarrhea was assayed in cultured human epithelial (HEp-2) cells. Twenty-one of 24 strains were invasive under the test conditions. Infection with Y. enterocolitica was characterized clinically by exudative diarrhea in 11 cases. Polymorphonuclear leukocytes were demonstrated in the feces from all three cases of exudative diarrhea studied. The results suggest a correlation between enteroinvasiveness of Y. enterocolitica, presence of leukocytes in feces, and clinical exudative diarrhea.