β-Lactamase Producing Escherichia coli Encoding blaCTX-M and blaCMY Genes in Chicken Carcasses from Egypt

Abstract

Escherichia coli with multidrug resistance and β-lactamase genes may constitute a great public health hazard due to the potential for their transmission to humans through the food chain. This study determined the prevalence, antibiotic resistance profiles, phylogroups, and β-lactamase genes of E. coli isolates from chicken carcasses marketed in Mansoura, Egypt. Interestingly, E. coli was detected in 98% (98/100) of the chicken carcasses examined, which seemed among the highest contamination rates by E. coli worldwide. From the 425 genetically verified uidA gene-positive E. coli, 85 isolates were further studied for antimicrobial resistance profiles, phylogroups, and β-lactamase genes. Interestingly, 89.41% of E. coli (76/85) strains tested against 24 different antibiotics were multidrug-resistant. Of the examined 85 E. coli isolates, 22 (25.88%) isolates harbored bla_CTX-M and were resistant to ampicillin, cefazoline, and ceftriaxone, while three of them were resistant to ceftazidime besides. Nine (10.59%) E. coli strains harbored AmpC- β-lactamase bla_CMY and were resistant to ampicillin. One isolate co-carried bla_CMY and bla_CTX-M genes, though it was negative for the bla_TEM gene. Of the 35 isolates that harbored either extended-spectrum β-lactamase (ESBL) and/or AmpC β-lactamase genes, six strains (17.14%) were assigned to pathogenic phylogroup F and one to phylogroup E, whereas 28 (80%) isolates belonged to commensal phylogenetic groups.

Keywords: E. coli; chicken carcasses; multidrug resistance; phylogroups; β-lactamase.

Figure 1

Number of E. coli isolates identified depending on colonial morphology, biochemical and molecular identification.

Figure 2

Antimicrobial resistance profiles of E. coli derived from poultry carcasses (n = 85) tested against 24 antibiotics in Egypt: ampicillin (R ≥ 32 μg/mL), ampicillin/sulbactam (R ≥ 32/16 μg/mL), doripenem (R ≥ 4 μg/mL), ticarcillin/clavulanic (R ≥ 128/2 μg/mL), aztreonam (R ≥ 16 μg/mL), cefazolin (R ≥ 32 μg/mL), ceftriaxone (R ≥ 4 μg/mL), ceftazidime (R ≥ 16 μg/mL), cefepime (R ≥ 16 μg/mL), ciprofloxacin (R ≥ 4 μg/mL), levofloxacin (R ≥ 8 μg/mL), piperacillin (R ≥ 128 μg/mL), gentamicin (R ≥ 16 μg/mL), tetracycline (R ≥ 16 μg/mL), tobramycin (R ≥ 16 μg/mL), amikacin (R ≥ 64 μg/mL), piperacillin/tazobactam (R ≥ 128/4 μg/mL), ertapenem (R ≥ 2 μg/mL), trimethoprim/sulphamethoxazole (R ≥ 4/76 μg/mL), imipenem (R ≥ 4 μg/mL), minocycline (R ≥ 16 μg/mL), meropenem (R ≥ 4 μg/mL), nitrofurantoin (R ≥ 128-μg/mL), tigecycline (R ≥ 2 μg/mL). The minimum inhibitory concentration (MIC) breakpoints were carried out according to the CLSI [28] and EUCAST [29] guidelines; R: resistant.

Figure 3

Prevalence of different phylogroups among total Escherichia coli isolates (n = 85).