Drug resistance and lecithinase activity of Yersinia enterocolitica isolated from buffalo milk.

Two-hundred-and-seven samples of raw buffalo milk and 60 samples of pasteurized buffalo milk were screened for presence of Yersinia enterocolitica. The prevalence of Y. enterocolitica was found to be 24.1% in raw milk, however, no isolation could be made from the pasteurized milk samples. Cold enrichment in trypticase soy broth and alkali treatment methods were followed in this study. The majority of the isolates (62%) were found sensitive to all the antibiotics used and only a few (16%) were resistant to two or more than two antibiotics. The incidence of Y. enterocolitica showed seasonal variations. Incidence was much higher (25-50%) during the winter season as compared to the summer (0-17%). The incidence of lecithinase production was high (40-50%) in Yersinia isolates resistant to one or two antibiotics.