鲍曼不动杆菌RND主动外排泵的表达与耐药性的关系

目的检测鲍曼不动杆菌耐药结节分化家族(RND)外排系统的分布,探索其表达与耐药性的关系。方法对南昌大学第一附属医院临床标本分离的59株多重耐药鲍曼不动杆菌进行细菌的鉴定与药敏分析,采用PCR技术检测鲍曼不动杆菌中RND主动外排系统的分布情况,比较不同耐药表型的鲍曼不动杆菌间外排泵基因的表达情况,分析其表达量与耐药的关系,并对RND外排系统的扩增产物进行测序。结果鲍曼不动杆菌对氨苄西林/舒巴坦、亚胺培南、庆大霉素、环丙沙星、左氧氟沙星耐药率高达93.2%、94.9%、88.1%、96.6%、52.5%。59株鲍曼不动杆菌经外排泵及整合子基因PCR扩增检测,adeR、adeS、adeB、adeJ、adeG基因的携带率分别为81.4%、91.5%、93.2%、100.0%、61.0%。不同菌株外排泵基因的表达均不相同,其中庆大霉素、亚胺培南、氨苄西林/舒巴坦耐药组与非耐药组鲍曼不动杆菌adeB、adeJ基因的表达量相比,差异均有统计学意义(均P0.05)。adeABC外排泵的调控基因adeR、adeS的碱基序列未出现基因突变或插入序列。结论 RND外排系统在鲍曼不动杆菌中普遍存在,RND外排系统中adeB、adeJ基因的表达水平升高与细菌对庆大霉素、亚胺培南、氨苄西林/舒巴坦的耐药性有关。

Relationship between expression and antimicrobial resistance of RND efflux pump of Acinetobacter baumannii

ObjectiveTo detect the distribution of resistance nodulation (RND) efflux pump system of Acinetobacter baumannii(AB), and explore the relationship between its’ expression and antimicrobial resistance.MethodsFifty nine strains of multidrug resistant AB isolated from clinical specimens in The First Affiliated Hospital of Nanchang University were identified and performed antimicrobial susceptibility analysis, distribution of RND efflux system of AB was detected by polymerase chain reaction(PCR), expression of efflux pump genes in different drug resistant phenotypes of AB was compared, relationship between the expression level and drug resistance was analyzed, amplified products of RND efflux system were sequenced.ResultsResistance rates of AB to ampicillin/sulbactam, imipenem, gentamicin, ciprofloxacin, and levofloxacin were 93.2%, 94.9%, 88.1%, 96.6%, and 52.5% respectively. PCR detection results of efflux pump and integron genes of 59 AB strains revealed that the carrying rates of adeR, adeS, adeB, adeJ, and adeG genes were 81.4%, 91.5%, 93.2%, 100.0%, and 61.0% respectively. The expression of efflux pump genes in different strains was different, expression levels of adeB and adeJ genes among gentamicin, imipenem, ampicillin/sulbactam resistant AB group and non resistant AB group were significantly different (all P<0.05). There was no mutation or insertion sequence in the base sequences of regulatory genes adeR and adeS of adeABC efflux pump.ConclusionRND efflux pump system is universally present in AB, the expression upregulation of adeB and adeJ genes in RND efflux pump system is related with antimicrobial resistance of bacteria to gentamycin, imipenem, and ampicillin sulbactam.