Using Molecular Techniques for Characterization of Escherichia coli Isolated from Water Sources in Egypt

Abstract

Failure to understand the importance of water quality exposes animals and human to the risk of diseases. Microbial contamination reminds a critical risk factor in drinking water in many parts of the world. Fifty water samples were investigated to detect the occurrence of coliforms. All E. coli isolates were serotyped and screened for virulence genes (hly, fliCh7, stx1, stx2 and eae genes). The results showed that 90 % of th e collected water samples were positive for coliforms. The highest coliforms detection rate was recorded among water samples collected from canals followed by drinking underground water, River Nile, agricultural drain, untreated sewage water, treated sewage water and well samples respectively. The predominant E. coli serotype isolated from the examined water samples was O128:K67 followed by O157: K, O111:K58 and O55:K59 - respectively. E. coli strains isolated from water sources were characterized by PCR and showed that 8 isolates carried stx1 gene (verocytotoxin 1) and 4 possessed stx2 gene (verocytotoxin 2). Intimin (eae), chromosomal flagellin type H7 of E. coli (fliCh7) and enterohemolysin (hly), virulence genes were detected in 21.4, 21.4 and 28.6 % of the isolates respectively. It could be concluded that water may be an important reservoir for E. coli infection and the risks of contracting enterotoxigenic (ETEC) and or enterohemorrh agic E. coli (EHEC) infections from contaminated water have been clearly established.