CHARACTERIZATION

The informally raw milk and Kareish cheese sold in Qena city (Upper Egypt) were analyzed to determine the presence of toxigenic E.coli. The isolates were screened for the presence of verotoxigenic E.coli (VTEC) and enterotoxigenic E.coli (ETEC) by Polymerase Chain Reaction (PCR). Bio-resistance to antimicrobial agents was evaluated by the disk diffusion method. E coli were recovered from 38 (76%) of raw milk and 11 (47.8%) of Kareish cheese samples. Three (6.1%) of the E.coli isolates were VTEC and none of them hat eaeA gene encoded a pathogenicity island typical of E.coli O157:H7 (EHEC). PCR of enterotoxins showed that only one isolate carried LT enterotoxins of ETEC. Bio-resistance was frequently observed to nalidixic acid (42.9%), ampicillin (32.7%), tetracycline (22.4%), trimethoprim-sulfamethoxazol (14.3%), ciprofloxacin (4.1%) and cefoxtin (2.0%). Results suggested a possibility of potential public health threat of E.coli originating from raw milk sources. Markets and consumers for raw milk and their products have existed in many parts of the world. Being a highly nutritious medium, therefore many bacteria including spoilage an