Prevalence of plasmid-mediated quinolone resistance determinants in ESBL Enterobacteriaceae clinical isolates over a 1-year period in a French hospital
Prevalence of plasmid-mediated quinolone resistance determinants in ESBL Enterobacteriaceae clinical isolates over a 1-year period in a French hospital
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DOI：
10.1016/j.patbio.2009.04.003
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发表时间：
2011-06-01
影响因子：
--
通讯作者：
Corvec, S.
中科院分区：
文献类型：
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作者：
Cremet, L.;Caroff, N.;Corvec, S.
在 2006 年南特大学医院回收的 47 株产广谱 β-内酰胺酶 (ESBL) 且对氟喹诺酮类药物敏感性降低的肠杆菌分离株中，对质粒介导的喹诺酮耐药 (PMQR) 决定簇（qnrA、qnrB、qnrS、aac(6')-Ib-cr 和 qepA）的流行率进行了调查。 qnr,通过PCR筛选aac(6')-Ib-cr和qepA基因，随后通过测序证实阳性结果。通过脉冲场凝胶电泳（PFGE）研究了阳性分离株之间的流行病学关系。分析了 qnr 阳性分离株的抗菌敏感性以及 gyrA 和 parC 基因喹诺酮耐药决定区 (QRDR) 中是否存在突变。 ESBL 基因通过 PCR 和测序进行表征。进行接合实验以确定携带qnr的质粒是否可自我转移。两种没有克隆相关性的肺炎克雷伯菌分离株（4.3%）携带 qnrS1 基因，但未检测到 qnrA 或 qnrB 阳性分离株。在 11 株大肠杆菌和 1 株肺炎克雷伯菌分离株中检测到 aac(6')-Ib-cr 基因。 47 个分离株均不携带 qepA 基因。与 QnrS1 相关的 ESBL 是 CTX-M-14 和 CTX-M-15。产生 CTX-M-15 的分离株对氟喹诺酮类药物高度耐药，并在 QRDR 和两个 PMQR 决定簇（qnrS1 和 aac(6')-Ib-cr）中携带三个突变。产生 CTX-M-14 的分离株表现出对氟喹诺酮类药物的敏感性或耐药性降低，但对萘啶酸没有耐药性。该菌株在单个 170 kb 可转移质粒上仅包含一个 qnr 基因，QRDR 中没有任何突变。总之，我们的研究表明，aac(6')-Ib-cr 基因存在于 2006 年南特大学医院收集的多克隆产 ESBL 肠杆菌分离株中，其患病率高于 qnr 基因。 (C) 2009 Elsevier Masson SAS。版权所有。
The prevalence of plasmid-mediated quinolone resistance (PMQR) determinants (qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA) was investigated in a collection of 47 extended-spectrum beta-lactamase (ESBL) producing enterobacterial isolates with reduced susceptibility to fluoroquinolones, recovered at Nantes University hospital, in 2006. qnr, aac(6')-Ib-cr, and qepA genes were screened by PCR, and positive results were subsequently confirmed by sequencing. The epidemiological relationship between positive isolates was studied by pulsed-field gel electrophoresis (PFGE). qnr-positive isolates were analyzed for antimicrobial susceptibility and presence of mutations in the quinolone resistance-determining region (QRDR) of gyrA and parC genes. ESBL genes were characterized by PCR and sequencing. Conjugation experiments were performed to determine whether the qnr-carrying plasmids were self-transferable. Two Klebsiella pneumoniae isolates (4.3%), not clonally related, harboured a qnrS1 gene, whereas no qnrA- or qnrB-positive isolate was detected. The aac(6')-Ib-cr gene was detected in 11 Escherichia coli and one K. pneumoniae isolates. None of the 47 isolates carried the qepA gene. ESBLs associated with QnrS1 were CTX-M-14 and CTX-M-15. The CTX-M-15 producing isolate was highly resistant to fluoroquinolones and harboured three mutations in the QRDR and two PMQR determinants (qnrS1 and aac(6')-Ib-cr). The CTX-M-14-producing isolate exhibited reduced susceptibility or resistance to fluoroquinolones without resistance to nalidixic acid. This strain harboured only a qnr gene on a single 170 kb transferable plasmid, without any mutation in the QRDR. In conclusion, our study showed that aac(6')-Ib-cr gene had occurred in multiclonal ESBL-producing enterobacterial isolates collected at Nantes University hospital in 2006, with a higher prevalence than qnr genes. (C) 2009 Elsevier Masson SAS. All rights reserved.