الفهرس 
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Abstract
ABSTRACT
Amongst poising food bacterial pathogen, E. coli remains foremost type worldwide. The emergence of multidrug resistant E. coli isolated from animal and animal products become the main wary of food safety and community health authorities. The present study was undertaken to investigate incidence, ultimate main serovars and the antimicrobial sensitivity patterns of E. coli isolated from animals and animal products. The genetic diversity among the isolates was evaluated by multiplex PCR. Results demonstrated that out of the 300 examined samples (75 mastitic cow’s milk, 77 mastitic buffalo’s milk, 40 cattle meat, 43 buffaloes meat and 65 chicken meats), 60 isolates (20 %) had been identified as E. coli depending on cultural characteristic and biochemical identification. 30 of 60 suspected isolated E. coli examined by VITEK2 and serologically identified, results revealed that 8 showed low discrimination for E. coli and were non-typeable, while 22 were positive, showed excellent level of identification for E. coli and were identified serologically. Thirteen different serotypes were identified, where the obtained isolates were categorized as O26:H11 (4/22, 18%), O91:H21 (3/22, 13.6%), O111:H2 (2/22, 9%), O146:H21 (2/22, 9%), O1:H7 (1/22, 4.5%), O55:H7 (1/22, 4.5%), O119:H6 (1/22, 4.5%), O121:H7 (1/22, 4.5%), O78 (2/22, 9%), O125:H21 (2/22, 9%), O128:H2 (1/22, 4.5%), O159 (1/22, 4.5%), and O44:H18 (1/22, 4.5%). The isolates were further tested for antimicrobial resistance against 14 commercial antibiotics. The acquired results showed that the isolates were resistant to erythromycin (22/22, 100٪), streptomycin (21/22, 95.5٪), nalidixic acid (17/22, 80٪), clindamycin (14/22, 63.6٪) and sulphamethozole (11/22, 50٪). Lower resistance rate was observed to cephalothin (9/22, 40.9٪), tetracycline (7/22, 31.8٪), ampicillin (6/22, 27.3٪), colistin (5/22, 22.7٪), ciprofloxacin (5/22, 22.7٪), amikacin (4/22, 18.2٪), levofloxacin (2/22, 9.1٪), gentamycin (2/22, 9.1٪) and meropenem (1/22, 4.5٪).
Findings of virulence genes’ multiplex PCR revealed that the eaeA gene was successfully amplified in O26:H11; stx1 gene was successfully amplified in O26:H11, O55:H7, O91:H21, O111:H2, O119:H6, O128:H2 and O146:H21 serogroups but stx2 gene was successfully amplified in O1:H7, O26:H11, O78, O91:H21, O111:H2, O119:H6 and O125:H21. O91:H21, O111:H2 and O119:H6 serogroups carried both (stx1 and stx2) genes, O26:H11 serogroup carried (stx1, stx2 and eae) genes and O44:H18, O121:H7 and O159 serogroups were negative for these genes. Findings of multiplex PCR of β-lactamase antimicrobial resistance genes showed that blaOXA gene was successfully amplified in O26:H11 only; blaCTX-M1 gene was successfully amplified in O78 and O121:H7 serogroups but blaTEM gene was successfully amplified in O26:H11, O91:H21, O111:H2 and O125:H21. O26:H11 serogroup carried both (blaOXA and blaTEM) genes and O1: H7, O44:H18, O55:H7, O119:H6, O128: H2, O146:H21 and O159 serogroups were negative for (blaOXA, blaCTX-M and blaTEM) genes.
Key words: E. coli, VITEK2, Serology, PCR, antimicrobial resistance, virulence genes.