Prevalence of plasmid-mediated quinolone resistance in Escherichia coli isolated from diseased animals in Taiwan

Abstract

Escherichia coli (E. coli)s a zoonotic pathogen that often causesiarrhea, respiratoryiseases or septicemian animals. Fluoroquinolones are antimicrobial agents used to treat pathogenic E. colinfections. In this study, 1,221 E. coli strains weresolated betweenarch, 2011 and February, 2014. The results of the antimicrobial susceptibility testing showed a high prevalence of quinolone resistance. The antimicrobial resistance rates of these E. colisolates toalidixic acid (NAL) were 72.0%n swine, 81.9%n chickens, 81.0%n turkeys, 64.0%nucks and 73.2%n geese. Among thesesolates, the positive rate for the plasmid-mediated quinolone resistance (PMQR)eterminant was 14.8% (181/1,221), theetection rate for qnrS1 was the highest (10.2%), followed by aac(6′)-Ib-cr (4.5%) and qnrB2 (0.3%). The quinolone-resistanceetermining regions (QRDRs) analysis for the PMQR-positivesolates showed that the strains with mutations at codon 83 or 87n GyrA were resistant to NAL. To the best of our knowledge, thiss the first report of occurrence of qnrB2, qnrS1 and aac(6′)-Ib-cr genes and high frequency (56.4%, 102/181) of mutationn gyrA or parC among PMQR-positive E. coli strainserived fromiseased animalsn Taiwan.