Antimicrobial Resistance among Commensal Escherichia coli from Broilers in Turkey

In this study it was aimed to determine the antimicrobial susceptibility, resistance mechanisms, the prevalence of class 1 and 2 integrons and phylogenetic groups in 300 Escherichia coli isolates from poultry farms in Turkey. The antimicrobial susceptibility of the isolates was determined by disk diffusion method, the occurence of antimicrobial resistance genes, class 1 and 2 integrons and phylogenetic grouping were investigated by polymerase chain reaction (PCR). In ciprofloxacin resistant E. coli isolates, gyrA and parC mutations were detected by mismatch amplification mutation assay-PCR (MAMA-PCR). All extended spectrum β-lactamase (ESBL) and plasmidic AmpC β-lactamase (pAmpC) positive E. coli isolates were investigated for presence of ESBL and pAmpC genes, and following DNA sequencing. Antimicrobial test results revealed that 86.7% of the isolates had multidrug resistance (MDR) phenotype. MDR profiles were observed in all of the integron-positive isolates, whereas 81.4% of non-integron-carrying isolates were MDR (p<0.001). Phylogenetic analysis showed that integron carrying isolates mainly belonged to D (54.5%), A (32.5%), B1 (10.6%) and B2 (2.4%). The results indicate a high level of MDR and prevalence of class 1 and 2 integrons among commensal E. coli from Turkish broiler flocks. Urgent measures should be taken to promote prudent use of antimicrobials and to limit use of antimicrobials in broiler flocks.