Mutations in DNA Gyrase and Topoisomerase IV in Ciprofloxacin-Nonsusceptible Extended-Spectrum beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae: a Statistical Analysis

作者：Park Kyung Sun; Yang Hyung Seok; Nam You Sun; Lee Hee Joo^*

来源：Clinical Laboratory, 2017, 63(3): 535-541.

DOI：10.7754/Clin.Lab.2016.160924

• ESBL
• QRDRs
• PMQR
• ciprofloxacin resistance

Background: We investigated mutations in the quinolone resistance-determining region (QRDR) of ciprofloxacinnonsusceptible extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae by a statistical analysis. Methods: We collected 97 clinical isolates of ciprofloxacin-nonsusceptible ESBL-producing E. coli (55 strains) and K. pneumoniae (42 strains) from a tertiary-care university hospital in Seoul, Republic of Korea, between 2006 and 2008. The QRDR of the gyrA, gyrB, parC, and parE genes were amplified by PCR and sequenced. Results: Most E. coli isolates(53/55; 96.4%) with a minimum inhibitory concentration of >= 64 mg/L against ciprofloxacin had double mutations in gyrA(Ser-8 -> Leu and Asp-87 -> Asn) and at least one mutation in parC(Ser-80 -> Ile or Glu-84 -> Val), with or without one in parE. Fifty E. coli(90.9%) isolates had a mutation in parE, of which Ile-529 -> Leu (70.9%) was the most frequent. However, we could not find statistically significant variables in increasing ciprofloxacin resistance in E. coli isolates. Thirty-six K pneumoniae isolates (36/42; 85.7%) had at least one mutation in gyrA, gyrB, or parC, and the mutation in gyrA might have been associated with plasmid-mediated quinolone-resistance (PMQR). Ser-80 -> Ile in parC and aac(6')-lb-cr in the K. pneumoniae isolates were significantly associated with an increased MIC of ciprofloxacin by ordinal logistic regression analysis. Conclusions: The Ser-80 -> Ile in parC and aac(6')-Ib-cr in K. pneumoniae are supposed to play an important role in increased ciprofloxacin resistance, but statistically significant variables could not be found in E. coli isolates in the present study.

• 出版日期2017