Yersinia enterocolitica and Y. enterocolitica-like bacteria isolated from healthy humans in Norway.

Faeces samples from a total of 397 presumably healthy students in Norway were collected during April to September, 1979. Twenty strains of Y. enterocolitica and Y. enterocolitica-like bacteria were isolated from 10 (3%) of these students. Six students harboured 2-4 antigenically distinct strains. Of the total of 20 strains, 14 were typical Y. enterocolitica isolates, representing five different serogroups (4, 5, 6, 7-8, 13-7 and non-agglutinable). The remaining six strains were tentatively designated "y. enterocolitica-like bacteria". They showed atypical reactions with respect to one or more of the following characters: fermentation of rhamnose, sucrose, cellobiose and sorbose. The strains recovered from healthy humans in this work were similar to strains previously isolated from wild-living mammals, fish and water in Scandinavia. Nine strains produced enterotoxin at 22 degrees C but not at 37 degrees C.