Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Microbiology Department, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
Microbiology Department, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
J Glob Antimicrob Resist. 2019 Jun;17:39-43. doi: 10.1016/j.jgar.2018.11.003. Epub 2018 Nov 13.
This study assessed genetic alterations in gyrA, gyrB, parC and parE and the prevalence of plasmid-mediated quinolone resistance (PMQR) genes among Escherichia coli and Klebsiella pneumoniae isolates from urinary tract infections (UTIs) in Azerbaijan, Iran.
A total of 205 clinical isolates of E. coli (n=177) and K. pneumoniae (n=28) were obtained from UTIs. Antimicrobial susceptibility was determined by disk diffusion and agar dilution assays. The presence of PMQR genes was determined by PCR, and sequencing of the gyrA, gyrB, parC and parE was performed.
The rate of fluoroquinolone (FQ) resistance among the isolates was 77.1%. The Ser83Leu mutation in gyrA was observed in all 60 FQ-resistant isolates selected for direct sequencing. The second most common mutation in gyrA was Asp87Asn. Frequent mutations in parC were Ser80Ile and Glu84Val. Ser359Ala+Ser367Thr and Gly385Cys mutations in gyrB were identified in one isolate each of K. pneumoniae and E. coli, respectively. The parE gene had mutations at Ile529Leu, Ser458Ala and Leu416Phe. Overall, PMQR determinants were identified in 90% of E. coli and 100% of K. pneumoniae. The prevalence of PMQR genes was as follows: aac(6')-Ib-cr, 71.7%; oqxB, 51.7%; oqxA, 36.7%; qnrB, 28.3%; qnrS, 21.7%; qnrD, 16.7%; qepA, 5.0%; qnrA, 1.7%; and qnrC, 1.7%.
FQ resistance rates were high. Mutations in DNA gyrase and topoisomerase IV and the prevalence of PMQR genes in E. coli and K. pneumoniae isolates were alarming. Moreover, the combination of these resistance mechanisms plays an important role in high-level FQ resistance.
本研究评估了阿塞拜疆和伊朗尿路感染（UTI）分离的大肠埃希菌和肺炎克雷伯菌中 gyrA、gyrB、parC 和 parE 的基因改变以及质粒介导的喹诺酮耐药（PMQR）基因的流行情况。
共从 UTI 中获得 205 株大肠埃希菌（n=177）和肺炎克雷伯菌（n=28）的临床分离株。采用纸片扩散法和琼脂稀释法测定抗菌药物敏感性。通过 PCR 检测 PMQR 基因的存在，并对 gyrA、gyrB、parC 和 parE 进行测序。
分离株中氟喹诺酮（FQ）耐药率为 77.1%。选择用于直接测序的 60 株 FQ 耐药株均观察到 gyrA 中的 Ser83Leu 突变。gyrA 中第二常见的突变是 Asp87Asn。parC 中常见的突变是 Ser80Ile 和 Glu84Val。肺炎克雷伯菌和大肠埃希菌各有 1 株分离株存在 gyrB 的 Ser359Ala+Ser367Thr 和 Gly385Cys 突变。parE 基因在 Ile529Leu、Ser458Ala 和 Leu416Phe 处发生突变。总体而言，大肠埃希菌和肺炎克雷伯菌的 PMQR 决定因素分别为 90%和 100%。PMQR 基因的流行率如下：aac(6')-Ib-cr，71.7%；oqxB，51.7%；oqxA，36.7%；qnrB，28.3%；qnrS，21.7%；qnrD，16.7%；qepA，5.0%；qnrA，1.7%；和 qnrC，1.7%。
FQ 耐药率很高。DNA 回旋酶和拓扑异构酶 IV 的突变以及大肠埃希菌和肺炎克雷伯菌分离株中 PMQR 基因的流行令人震惊。此外，这些耐药机制的组合在高水平 FQ 耐药中起着重要作用。
