Abstract
The presence of E. coli in fresh-marketed fish indicates recent contamination and is usually attributed to infected handlers or storage on contaminated ice. E. coli may be transmitted to human during handling of fish or consumption of raw or under cooked fish. Human infection (foodborne illnesses) range from mild diarrhea to life threatening hemorrhagic colitis (HC), haemolytic uremic syndrome (HUS). In this study, 200 fish samples from gills, musculature, surface and intestine, 100 water samples and 100 hand swaps from sellers’ hand were collected from Kafrelzyate and Tanta retail markets in Gharbiya. The samples were examined for the presence of E. coli. Forty-four samples (8 gills, 3 musculature, 8 surface, 9 intestine, 9 water and 7 hands of sellers) were positive to E. coli. The identification was carried out by both biochemical methods and PCR. The 44 isolates were tested for antimicrobial resistance using 10 antimicrobial discs and the results revealed multiple antimicrobial resistance. Serological identification of the isolates showed the presence of O44 (15.9 %), O125 (20.4 %), O172 (13.6 %), O103 (6.8 %) and O119 (18.1 %). The stx1, stx2 and eaeA virulence genes were detected by PCR in the isolates.

Key words: E. coli, virulence genes, Egypt, Nile Tilapia, serotypes