A total samples (616) were collected from bovine (100 calf`s fecal samples; 216 calf`s internal organs; 100 cow`s fecal samples and 200 cow`s internal organs), the animals showed profuse diarrhea. The samples were submitted for the isolation and identification of E.coli O157:H7. The identified isolates were examined for their susceptibility to 16 antimicrobial agents. Multiplex PCR was used for the detection of plasmid-mediated ampC β-lactamases (MAABLs) in isolated strains. E.coli O157:H7 isolated with rate of (2%) from the fecal sample of calves and cows. While only o.46% were isolated from internal organs of calves, meanwhile E.coli O157:H7 not isolated from cows samples.
The isolates showed multidrug resistance ranged from 6%- 100%. AmpC plasmid mediated β lactamas genes were detected in all isolates of E.coli O157:H7, where 3 isolates showed presence CMY-7, BIL-1 at fragment 462bp, one isolate showed the presence of DHA-1, DHA-2 at fragment 405bp and one isolate showed MIR-1T and ACT-1 were detected at a of LAT-1 to LAT-4, CMY-2 to fragment 302bp. PCR remains the gold standard for detection of plasmid AmpC 𝛽-lactamases.
This study may represent the first report of variants of MIR-1Tand ACT-1 𝛽-lactamase-producing E. coli in Egypt. Phenotypic methods alone may not reflect the true number of PMABLs producers. Genotypic methods need to be employed in national surveillance studies in Egypt.