STUDIES ON ECHERICIA COLI ISOLATED FROM MASTITIC CATTLE AND COMPARATIVE REVEALANCE TO HUMAN.

A total of 50 clinical mastitic milk samples, 42 sub clinical mastitic milk samples ( positive with California Mastitis Test) and 40 hand swabs from contact human were collected from different dairy farms at Gharbia governorate and investigated bacteriologically to isolate Ecshericia coli. Among clinical mastitic samples a total of 5 isolates E. coli (10%), from sub clinical mastitic samples 3 isolates (7.4%) were detected, while 3 isolates (7.5% ) were recovered from contact human hand swabs. E. coli isolates were serotyped under 6 different O serotypes (O 27 and O 55) isolated from contact human while (O6, O86, O114, O27 and O 157 ) isolated from mastitic milk . Antibiotic sensitivity revealed that all isolates were fully susceptible to enerofloxacin, ciprofloxacin, while all isolates were fully resistant to penicillin. E. coli serogrouped isolates were subjected to PCR for detection of Stx1 and Stx2 genes. 3 out of 7 serogrouped isolates (42.85%) were carried Stx2 gene (O55 and O27 from contact human and O86 from mastitic milk) while Stx1 gene was not detected . phylogenetic analysis for the sequence data of the Sxt2 gene of E. coli serogroupes revealed that Sxt2 gene isolated from mastitic milk of cattle is closely identical (100% identity) to Sxt2 gene isolated from contact human. In Conclusion , isolation of STEC from cattle might have potential pathogenicity for human. So that contact human should use sound hygienic measures during milking and management of these animals to avoid zoonotic infection.