Verotoxin-producing Escherichia coli - an environment-induced emerging zoonosis in and around Calcutta

With changes in livestock management practices and food processing industry , along with changes in people's food habits, many diseases have emerged. I nfection with verotoxin-producing Escherichia coli (VTEC) is one such illne ss. In the present study an attempt was made to isolate, identify and chara cterize VTEC strains with reference to the 0157: H7 serotype from animal, h uman sources and some food products with the aid of the available modern me thods. A total of 876 samples (330 animal, 184 human, 362 food samples) wer e screened for the presence of VTEC by conventional as well as PCR techniqu e. Seventeen VTEC strains (12 animal, one human and four food samples) were isolated. The isolation rate was higher in diarrhoeic animals (6.02%), fol lowed by diarrhoeic handler (3.12%) and raw beef (1.78%) samples. All strai ns showed the presence of the VT gene by PCR tests and were uniformly sensi tive to common antibiotics except tetracycline, cephalexin, dicloxacillin, erythromycin and lincomycin. Since all strains were isolated from various s ources of animal and human origin and all strains showed the presence of th e VT gene and uniform antibiogram, a zoonotic association is suggested. Thi s study marks the first report of isolation of VTEC strains from animal sou rces in India.