Purpose: The objective of this study was to analyze the resistance and virulence genotypes of ExPEC isolated from retail poultry meats to assess their food safety risks.
Methods: Fifty-seven ExPEC isolates from retail chicken (43) and turkey (14) meats were investigated for their susceptibility to 14 antibiotics using Sensititre system according to the CLSI’s guidelines. A DNA-microarray designed to detect 264 virulence genes and 96 antibiotic resistance genes as well as PCRs were used to determine their genotype.
Results: The most common resistance pattern was amoxicillin-clavulanic acid-ampicillin-cefoxitin-ceftiofur-ceftriaxone-tetracycline (43%). Resistance to sulfisoxazole, streptomycin and gentamicin was found in 16 (28.0%), 15 (26.3%) and 7 (12.3%) isolates, respectively. Except for gentamicin, resistance was more prevalent in chicken than in turkey. A total of 25, 16 and 9 isolates harbored 1-5, 6-10 and 11-17 resistance determinants, respectively. The β-lactamase blaCMY-2, blaOXA27, blaOXA2b and blaTEM genes were detected in 24 (42.1%), 16 (28.0%), 17 (29.8%) and 6 (10.5%) isolates, respectively. Other detected genes include those conferring resistance to aminoglycosides (aadA, aphA, aph3/strA), quinolone (aac6-1b-CR, qnrA) trimethoprims (dhfr-1, dhfr-15), tetracyclines (tetA, tetB, tetR) and sulfonamides (sul1, sul2). Class 1 integrons were found in 8 isolates. The number of detected virulence genes varied from 29 to 62. All 57 isolates harbored the following virulence genes: b(1121), csgA, csgE, gad, EcSf, hlyE, ibeB1a, ibeB1b, iucD, iut(A2), iut(upec), iutA, ompA, sitA and sitD.
Significance: This study shows that ExPEC from retail poultry meats can harbor multiple antibiotic resistance and virulence genes of clinical importance. The presence in retail poultry meats of such isolates harboring class D β-lactamases (blaOXA) with potential carbapenem hydrolyzing activity is of concern and raises a potential food safety risk.