Plasmid-mediated quinolone resistance in Escherichia coli strains isolated from animals in Turkey

Abstract

Chromosomal mutations and resistance genes transferred by plasmids are the main factors of quinolone resistance particularly in Escherichia coli strains isolated from both animals and humans. In this study a total of 259 E. coli strains were examined for the resistance to nalidixic acid and ciprofloxacin by agar dilution method and for the presence of qnrA, qnrB and qnrS genes that are known as plasmid-mediated quinolone resistance determinants by PCR. According to antimicrobial susceptibility tests 47 (50.0%) of 94 chicken, 3 (4.5%) of 66 sheep, 5 (9.6%) of 52 cattle and 3 (6.4%) of 47 dog E. coli strains were found to be resistant to ciprofloxacin. Among all plasmid-mediated quinolone resistance determinants that were investigated in this study, only qnrA gene was found in 5 (5.3%) of 94 E. coli chicken isolates. This is the sole report from Turkey that evaluated the plasmid-mediated quinolone resistance in animal isolates of E. coli strains.