Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia.
Eur Rev Med Pharmacol Sci. 2013 Jul;17(13):1744-7.
The ciprofloxacin resistance of Klebsiella (K.) pneumoniae is mediated primarily through alterations in type II topoisomerase (gyrA) gene and plasmid-mediated quinolone resistance-conferring genes (qnr). This study aimed to define the prevalence of plasmid-mediated quinolone resistance-conferring genes (qnr) and type II topoisomerase (gyrA) alterations of a population of ciprofloxacin-resistant (n = 21), intermediate (n = 8), and sensitive (n = 18) K. pneumoniae isolates obtained from a teaching hospital at Kuala Lumpur, Malaysia.
A multiplex PCR assay was performed for simultaneous detection of qnrA, qnrB and qnrS. Sequence analysis of the amplified gyrA and gyrB regions of the isolates were performed.
The findings in this study revealed the emergence of a high prevalence (48.9%) of qnr determinants in our isolates. Four variants of plasmid-mediated qnr determinants (qnrB1, qnrB6, qnrB10 and qnrS1) were detected from 11 (52.4%) ciprofloxacin-resistant, 5 (62.5%) intermediate and 7 (38.9%) sensitive isolates. gyrA alterations were detected from 18 (85.7%) ciprofloxacin-resistant isolates. Single gyrA alterations, Ser83→Tyr, Ser83→Ile, and Asp87→Gly, and double alterations, Ser83→Phe plus Asp87→Ala and Ser83→Tyr plus Asp87→Asn were detected. While ciprofloxacin resistance was significantly associated with gyrA alteration (Ser83, p = 0.003; Asp87, p = 0.005; double alteration, p = 0.016), no significant association of ciprofloxacin resistance was noted with the presence of qnr determinants (p = 0.283).
The findings in this study demonstrate the emergence of qnr determinants and gyrA alterations contributed to the development and spread of fluoroquinolone resistance in the Malaysian isolates.
肺炎克雷伯菌（K. pneumoniae）对环丙沙星的耐药性主要是通过 II 型拓扑异构酶（gyrA）基因突变和质粒介导的喹诺酮类耐药基因（qnr）的改变介导的。本研究旨在确定马来西亚吉隆坡一所教学医院分离的 21 株环丙沙星耐药（n = 21）、中介（n = 8）和敏感（n = 18）肺炎克雷伯菌分离株中，质粒介导的喹诺酮类耐药基因（qnr）和 II 型拓扑异构酶（gyrA）改变的流行情况。
采用多重 PCR 法同时检测 qnrA、qnrB 和 qnrS。对分离株扩增的 gyrA 和 gyrB 区进行序列分析。
本研究发现，我们的分离株中 qnr 决定簇的出现率很高（48.9%）。从 11 株（52.4%）环丙沙星耐药、5 株（62.5%）中介和 7 株（38.9%）敏感的分离株中检测到 4 种质粒介导的 qnr 决定簇（qnrB1、qnrB6、qnrB10 和 qnrS1）变体。18 株（85.7%）环丙沙星耐药的分离株检测到 gyrA 改变。检测到单个 gyrA 改变，Ser83→Tyr、Ser83→Ile 和 Asp87→Gly，以及双改变，Ser83→Phe 加 Asp87→Ala 和 Ser83→Tyr 加 Asp87→Asn。虽然环丙沙星耐药与 gyrA 改变显著相关（Ser83，p = 0.003；Asp87，p = 0.005；双改变，p = 0.016），但与 qnr 决定簇的存在无显著相关性（p = 0.283）。
本研究结果表明，qnr 决定簇和 gyrA 改变的出现导致了马来西亚分离株中氟喹诺酮类耐药的发展和传播。
