Genotyping of E.coli O157:H7 isolated from buffaloes [electronic resource].

Includes references.

The present study was concerned with E.coli O157:H7 isolated from buffalo-calves. From the total examined samples (215), which were collected from buffaloe farms, the total prevalence of E.coli isolated from buffaloe- calves was 47.91%, while in apparently healthy buffalo-calves and diarrheic buffalo-calves were 23% and 69.57% respectively. Further more, the incidences of sorbitol and non sorbitol fermenting E.coli were 44.65% and 3.26% respectively. Serological identification of E.coli O157:H7 from the total E.coli isolates revealed 93.2% negative (sorbitol fermenting E.coli) and 6.79% positive (non sorbitol fermenting E.coli). Hemagglutination (HA) activity of E.coli O157:H7 isolates showed that 100% positive HA [mannose resistant hemagglutination) (MRHA) and mannose sensitive hemagglutination (MSHA)] for human, guinea pig and chicken RBCs. While the test was 42.9% positive MRHA, 28.6% positive MSHA and 28.6% negative HA with bovine RBCs. The prevalence of enterotoxigenic E.coli O157:H7 isolates was 71.43%. Detection of α hemolytic E.coli O157:H7 was 29% while β-hemolytic E.coli O157:H7 was 43%. There were differences in isolates susceptibilities to different antimicrobial agents. Amoxicillin, colistin sulphate, flumequine, imipenem, had 100% susceptibilities on E.coli O157:H7 isolates. PCR assay for E.coli O157:H7 isolates revealed positive amplification of 255 bp fragment of shiga toxin 2 gene was observed in 80% of examined E.coli O157:H7 isolates. Moreover, positive amplification of 384 bp fragment of intimin gene was determined in 60% of examined E.coli O157:H7 isolates.

Summary in Arabic.

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