Pourakbari Babak, Yaslianifard Sahar, Yaslianifard Somaye, Mahmoudi Shima, Keshavarz-Valian Sepideh, Mamishi Setareh
Pediatrics Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Department of Microbiology, Islamic Azad University (Damghan Branch), Damghan, Iran.
Iran J Microbiol. 2016 Aug;8(4):249-256.
(PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of
In this study, 45 strains were isolated from patients admitted to Children's Medical Center Hospital, an Iranian referral hospital. Disk diffusion and Minimum Inhibitory Concentration (MIC) methods were used for determination of the patterns of resistance to antibiotics. Real-time PCR was used to investigate the expression level of genes of MexAB-OprM efflux pump.
Among 45 resistant PA isolates, the frequency of genes overexpression was as follows: (n=25, 55.5%), (n=24, 53.3%) and (n=16, 35.5%). In addition, in 28 strains (62%) overexpression was observed in one of the studied three genes of MexAB-OprM efflux pump.
In our study 28 isolates (62%) had increased expression level of efflux pumps genes, MexAB-OprM. Although the efflux pumps play important roles in increasing the resistance towards different antibiotics but the role of other agents and mechanisms in evolution of resistance should not be ignored. Since the concomitant overproduction of other Mex efflux systems might have additive effects on antibiotic resistance, the co-expressing of a multicomponent efflux pump is recommended. On the other hand, the concomitant overproduction of two Mex pumps might have additive effects on resistance to antibiotic. Therefore co-expressing of Mex efflux systems is recommended.
肺炎克雷伯菌是医院感染的重要原因之一，并且对多种抗生素具有内在抗性。在所有耐药-固氮-细胞分裂（RND）泵中，MexAB-OprM是首个被发现针对多类抗生素的外排泵。本研究旨在评估肺炎克雷伯菌临床分离株中表达MexAB-OprM的基因的表达水平。
在本研究中，从伊朗一家转诊医院儿童医学中心收治的患者中分离出45株菌株。采用纸片扩散法和最低抑菌浓度（MIC）法测定抗生素耐药模式。采用实时荧光定量PCR研究MexAB-OprM外排泵基因的表达水平。
在45株耐药肺炎克雷伯菌分离株中，基因过表达频率如下：（n = 25，55.5%），（n = 24，53.3%）和（n = 16，35.5%）。此外，在28株（62%）菌株中，MexAB-OprM外排泵的三个研究基因之一出现过表达。
在我们的研究中，28株分离株（62%）外排泵基因MexAB-OprM的表达水平升高。虽然外排泵在增加对不同抗生素的耐药性方面发挥重要作用，但其他因素和机制在耐药性演变中的作用也不应被忽视。由于其他Mex外排系统的同时过量表达可能对抗生素耐药性有累加效应，建议共表达多组分外排泵。另一方面，两个Mex泵的同时过量表达可能对抗生素耐药性有累加效应。因此建议共表达Mex外排系统。
