Detection of enterotoxigenic and invasive strains of Yersinia enterocolitica

Membrane filtrates and heavy cell suspensions of 11 strains of Yersinia enterocolitica isolated from a recent epidemic were examined respectively for enterotoxin activity and tissue invasiveness. Although no heat-labile enterotoxins were detected, some strains were found to possess heat-stable enterotoxins and to have the ability to penetrate the conjunctival epithelia of guinea pig eyes. These activites were detected only in cultures grown at 25 degrees C and not at 36 degrees C.