Identification of serotypes and virulence markers of Escherichia coli isolated from human stool and urine samples in Egypt.

PURPOSE: Haemorrhagic colitis and haemolytic-uremic syndrome are associated with Shiga-toxin producing Escherichia coli (STEC). There are others DEC (Diarrhoeagenic E. coli) pathotypes responsible for outbreaks and others toxins associated to these. Most clinical signs of disease arise as a consequence of the production of Shiga toxin 1 (Stx1), Stx2 or combinations of these toxins. Other major virulence factors include E. coli haemolysin (hlyA), and intimin, the product of the eaeA gene that is involved in the attaching and effacing adherence phenotype.
MATERIALS AND METHODS: In this study, the PCR assay was used to detect 12 E. coli genes associated with virulence (stx1, stx2, hylA, Flic h7 , stb, F41, K99, sta, F17, LT-I, LT-II and eaeA).
RESULTS: A total of 108 E. coli strains were serotyped into 64 typable strains. The investigated strains from the stool, 8/80 (10%) strains were O 164:K, while the 56/110 strains isolated from the urine were O126:K71 (44/110, 40%) and O 86:K 61 (12/110, 11%). The distribution pattern of the detected virulence genes was observed to be in the following order: F17 (10% from the stool and 44% from the urine), Sta (10% from the stool), hylA (10% from the stool and 44% from the urine), Stb (44% from the urine) and stx1 (27% from the urine). The 8 faecal strains encoded a combination of the F17, Sta and hylA genes, while the 56 urine strains encoded a combination of the F17 0+ Stb + hylA (44/110, 40%) and Stx1 only (12/60, 20%).
CONCLUSION: This is the first report on the molecular characterization of E. coli diarrhoeagenic strains in Egypt and the first report on the potential role of E. coli in diarrhoea and urinary tract infections in a localized geographic area where the people engage in various occupational activities.