PRODUCTION OF HEAT-STABLE, METHANOL-SOLUBLE ENTEROTOXIN BY YERSINIA-ENTEROCOLITICA

Isolates (7) of Y. enterocolitica serotype O:8, recovered during an outbreak of gastrointestinal illness, were examined for enterotoxin production. All 7 strains were enterotoxigenic in the suckling mouse model and 3 of 5 isolates tested produced keratoconjunctivitis in the guinea pig eye model (Sereny test). Enterotoxin was detected in broth supernatant fluid after 12 h of incubation at 25.degree. C. The toxin was not inactivated by exposure to 121.degree. C for 30 min or by storage at 4 or -40.degree. C for at least 5 mo. The enterotoxin was acid-stable and methanol-soluble. Methanol extraction did not affect its heat stability or enterotoxic activity in suckling mice. These physical characteristics plus limited ultrafiltration studies suggest that the enterotoxin is a low MW substance. Y. enterocolitica enterotoxin resembles Escherichia coli heat-stable enterotoxin in heat and pH stability, methanol solubility and enterotoxic activity in suckling mice. Its role in the pathogenesis of human diarrhea was not established.