Experimental and Advanced Pharmaceutical Research Unit, Faculty of Pharmacy, Ain shams University, Organization of African Unity St. Abbassia, POB: 11566, Cairo, Egypt.
Department of Microbiology and Immunology, Faculty of Pharmacy, Ain shams University, Organization of African Unity St. Abbassia, POB: 11566, Cairo, Egypt.
Infect Genet Evol. 2021 Oct;94:105010. doi: 10.1016/j.meegid.2021.105010. Epub 2021 Jul 20.
Enterococci are opportunistic members of intestinal microbiota with notable ability to transmit antimicrobial resistance genes. Among the different resistance mechanisms, multidrug efflux is evolving as a huge problem in conferring multidrug resistance to bacterial cells because these pumps extrude a broad range of antimicrobials. Therefore, the aim of this work was to evaluate role of efflux pumps in the development of multi-drug resistance in Enterococci through studying the antimicrobial resistance profiles of Enterococci isolates, phenotypically and genotypically investigating the role of active efflux pumps in development of resistance, in addition to characterizing the most common efflux pump genes. The study involved the recovery of 149 Enterococci isolates from specimens of patients suffering infections in some hospitals in Egypt. Antimicrobial resistance profiles of isolates showed that only 1.3% of the isolates were resistant to each of linezolid, daptomycin, and fosfomycin. The highest resistance was to ampicillin (60.4%) while 47 of the isolates (31.54%) were found to be multidrug-resistant. Efflux pumps have shown to have a significant role in erythromycin resistance in 11 isolates (23.4% of MDR isolates) as indicated by an 8 or more fold decrease in minimum inhibitory concentration in the presence of the efflux pump inhibitor, carbonyl cyanide m- chlorophenylhydrazone (CCCP). End point PCR was used to detect efflux pump genes lsaE, msrC, and mefA in the 11 isolates at which efflux pumps were found to play a significant role in resistance. Nine out of the 11 isolates (81.8%) were found to carry lsaE gene. This gene was inserted into pUC21 vector and cloned into DH5α E. coli resulting in successful transformation and expression of erythromycin resistance in this host. Finally, sequencing of the lsaE gene was carried out. To the best of our knowledge, this is the first report on the cloning of lsaE gene from MDR Enterococcus isolates.
肠球菌是肠道微生物群中的机会性成员，具有显著传播抗菌药物耐药基因的能力。在不同的耐药机制中，多药外排正在成为赋予细菌细胞多药耐药性的一个巨大问题，因为这些泵可以排出广泛的抗菌药物。因此，本工作旨在通过研究肠球菌分离株的抗菌药物耐药谱，表型和基因型研究主动外排泵在耐药发展中的作用，以及表征最常见的外排泵基因，评估外排泵在肠球菌多药耐药发展中的作用。本研究涉及从埃及几家医院感染患者的标本中回收 149 株肠球菌分离株。分离株的抗菌药物耐药谱显示，只有 1.3%的分离株对利奈唑胺、达托霉素和磷霉素耐药。最高的耐药性是氨苄西林（60.4%），而 47 株（31.54%）被发现为多药耐药。外排泵在 11 株（MDR 分离株的 23.4%）红霉素耐药中表现出显著作用，这表明在存在外排泵抑制剂羰基氰化物 m-氯苯腙（CCCP）时，最小抑菌浓度降低了 8 倍以上。终点 PCR 用于检测 11 株分离株中发挥重要作用的外排泵基因 lsaE、msrC 和 mefA。在 11 株分离株中，发现 9 株（81.8%）携带 lsaE 基因。该基因被插入 pUC21 载体并克隆到 DH5α E. coli 中，导致该宿主成功转化和表达红霉素耐药性。最后，对 lsaE 基因进行了测序。据我们所知，这是首次从 MDR 肠球菌分离株中克隆 lsaE 基因的报道。
