Machuca Jesús, Agüero Jesús, Miró Elisenda, Conejo María Del Carmen, Oteo Jesús, Bou Germán, González-López Juan José, Oliver Antonio, Navarro Ferran, Pascual Álvaro, Martínez-Martínez Luis
Unidad Clínica Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Sevilla, España; Red Española de Investigación en Patología Infecciosa (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, España.
Red Española de Investigación en Patología Infecciosa (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, España; Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla-IDIVAL, Santander, España; Departamento de Biología Molecular, Universidad de Cantabria, Santander, España.
Enferm Infecc Microbiol Clin. 2017 Oct;35(8):487-492. doi: 10.1016/j.eimc.2016.05.006. Epub 2016 Jun 23.
Quinolone resistance in Enterobacteriaceae species has increased over the past few years, and is significantly associated to beta-lactam resistance. The aim of this study was to evaluate the prevalence of chromosomal- and plasmid-mediated quinolone resistance in acquired AmpC β-lactamase and/or carbapenemase-producing Enterobacteriaceae isolates.
The presence of chromosomal- and plasmid-mediated quinolone resistance mechanisms [mutations in the quinolone resistance determining region (QRDR) of gyrA and parC and qnr, aac(6')-Ib-cr and qepA genes] was evaluated in 289 isolates of acquired AmpC β-lactamase- and/or carbapenemase-producing Enterobacteriaceae collected between February and July 2009 in 35 Spanish hospitals.
Plasmid mediated quinolone resistance (PMQR) genes were detected in 92 isolates (31.8%), qnr genes were detected in 83 isolates (28.7%), and the aac(6')-Ib-cr gene was detected in 20 isolates (7%). qnrB4 gene was the most prevalent qnr gene detected (20%), associated, in most cases, with DHA-1. Only 14.6% of isolates showed no mutations in gyrA or parC with a ciprofloxacin MIC of 0.5mg/L or higher, whereas PMQR genes were detected in 90% of such isolates.
qnrB4 gene was the most prevalent PMQR gene detected, and was significantly associated with acquired AmpC β-lactamase DHA-1. PMQR determinants in association with other chromosomal-mediated quinolone resistance mechanisms, different to mutations in gyrA and parC (increased energy-dependent efflux, altered lipopolysaccharide or porin loss), could lead to ciprofloxacin MIC values that exceed breakpoints established by the main international committees to define clinical antimicrobial susceptibility breakpoints.
在过去几年中，肠杆菌科细菌对喹诺酮类药物的耐药性有所增加，且与β-内酰胺类耐药性显著相关。本研究的目的是评估获得性产AmpCβ-内酰胺酶和/或碳青霉烯酶的肠杆菌科分离株中染色体介导和质粒介导的喹诺酮类耐药性的流行情况。
对2009年2月至7月间在西班牙35家医院收集的289株获得性产AmpCβ-内酰胺酶和/或碳青霉烯酶的肠杆菌科分离株，评估其染色体介导和质粒介导的喹诺酮类耐药机制[gyrA和parC喹诺酮耐药决定区（QRDR）的突变以及qnr、aac(6')-Ib-cr和qepA基因]。
在92株分离株（31.8%）中检测到质粒介导的喹诺酮类耐药（PMQR）基因，在83株分离株（28.7%）中检测到qnr基因，在20株分离株（7%）中检测到aac(6')-Ib-cr基因。qnrB4基因是检测到的最常见的qnr基因（20%），在大多数情况下与DHA-1相关。仅14.6%的分离株在gyrA或parC中无突变且环丙沙星MIC为0.5mg/L或更高，而在90%的此类分离株中检测到PMQR基因。
qnrB4基因是检测到的最常见的PMQR基因，且与获得性AmpCβ-内酰胺酶DHA-1显著相关。与其他染色体介导的喹诺酮类耐药机制（不同于gyrA和parC中的突变，如能量依赖性外排增加、脂多糖改变或孔蛋白丢失）相关的PMQR决定簇可能导致环丙沙星MIC值超过主要国际委员会确定的定义临床抗菌药物敏感性断点的断点值。
