Antibiotic resistance and especially multiresistance in Enterococci, is a serious public health issue especially in infections of immunocompromised patients. EfrAB is a heterodimeric multidrug ATP-binding cassette (ABC) transporter that causes endogenous resistance to antimicrobials including fluoroquinolones in Enterococcus spp. The aim of this study was to seek the gene expression rate and role of efrAB efflux pump in ciprofloxacin resistant Enterococcus faecalis and Multilocus Sequence Typing (MLST) of multiresistant isolates. Phenotypic and genotyping identification of 80 E. faecalis isolates were performed. Minimum inhibitory concentrations (MICs) to ciprofloxacin (CIP) were measured with and without carbonylcyanide 3-chlorophenylhydrazone (CCCP) by broth microdilution. After DNA extraction and sequencing for detection of efrA and efrB genes, the efrAB efflux positive isolates that were resistant to ciprofloxacin and showed decrease of ciprofloxacin MIC range were identified. Isolates that exhibited decrease in ciprofloxacin MIC range from two to ten folds were assessed for biofilm formation and finally, the expression levels of efrB, efrA genes were measured by quantitative Real-Time PCR (qRT-PCR). High rates of resistance to tetracycline and minocycline and low rates of resistance to the most antibiotics used in this study were detected. The results in this study indicated that the incidence of Multiple drug resistance (MDR) was 23.7% and all isolates that were resistant to ciprofloxacin revealed several degrees of overexpression in efrA and efrB genes. Our study found two ST480 and one ST847 in E. faecalis isolates. In conclusion, despite of low frequency of resistance to the most antibiotics and MDRs in our region, we found one ST480 isolate with resistance to eight antibiotics that also exists in other parts of the world.

中文翻译：

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伊朗粪肠球菌 ST480、ST847 中 efrAB 外排泵的上调。

抗生素耐药性，尤其是肠球菌的多重耐药性，是一个严重的公共卫生问题，尤其是在免疫功能低下患者的感染中。EfrAB 是一种异二聚体多药 ATP 结合盒 (ABC) 转运蛋白，可导致肠球菌属中对包括氟喹诺酮在内的抗菌剂产生内源性耐药。本研究的目的是探索 efrAB 外排泵在耐环丙沙星粪肠球菌和多重耐药菌株多位点序列分型 (MLST) 中的基因表达率和作用。对 80 株粪肠球菌进行了表型和基因分型鉴定。使用和不使用羰基氰化物 3-氯苯腙 (CCCP) 通过肉汤微量稀释测量对环丙沙星 (CIP) 的最低抑菌浓度 (MIC)。经过DNA提取和测序检测efrA和efrB基因后，鉴定出对环丙沙星有抗药性并表现出环丙沙星 MIC 范围降低的 efrAB 外排阳性分离株。对环丙沙星 MIC 降低 2 至 10 倍的分离株进行生物膜形成评估，最后，通过定量实时 PCR (qRT-PCR) 测量 efrB、efrA 基因的表达水平。检测到对四环素和米诺环素的高耐药率以及对本研究中使用的大多数抗生素的低耐药率。本研究的结果表明，多重耐药性 (MDR) 的发生率为 23.7%，并且所有对环丙沙星耐药的分离株都显示 efrA 和 efrB 基因有几种程度的过度表达。我们的研究在粪肠球菌分离物中发现了两种 ST480 和一种 ST847。综上所述，