[Estimation of probiotics by infection model of infant rabbit with enterohemorrhagic Escherichia coli O157:H7].

We examined the preventative effect against enterohemorrhagic Escherichia coli O157:H7 (EHEC) infection in rabbits on administration of probiotics contained in Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus. The probiotics were administered to 5 days old Japanese white rabbits throughout the experiment. Inoculation of 10(6) colony forming units (CFUs) of EHEC per rabbit was tried 8 days after birth. Three days after EHEC inoculation, in the control group (not administered probiotics), diarrhea was observed in approximately 80% of the rabbits, on the other hand, in the group administered probiotics, rabbits showed diarrhea in 15%. In necropsy, the number of EHEC in the contents of the cecum and the number of attaching and effacing (AE) lesions were fewer in the probiotics group than in the control group. These results suggest that infant rabbits are useful as a colitis model for EHEC, and the probiotics are effective for the prevention of the growth of EHEC in the intestine and for diarrhea.