AdeABC外排泵在鲍曼不动杆菌对亚胺培南耐药中的作用研究

Role of AdeABC efflux pump involved in resistance to imipenem of Acinetobacter baumannii

目的探讨AdeABC外排泵在鲍曼不动杆菌对亚胺培南耐药中的作用。方法收集亚胺培南耐药鲍曼不动杆菌(imipenem resistant acinetobacter baumannii,IRAB)和亚胺培南敏感株(imipenem-sensitive Acinetobacter baumannii,ISAB)各30株。用琼脂稀释法检测其对抗菌药物的最低抑菌浓度(minimum inhibition concentrations,MIC),加入外排泵抑制剂PAβN检测外排泵表型;用聚合酶链反应(polymerase chain reaction,PCR)、逆转录实时荧光定量PCR(Real time fluorescence quantitative PCR,RT-qPCR)分别检测adeB基因阳性率及相对表达量。DNA重组技术将adeABC-RS基因转入adeB阴性的ISAB,测定MIC变化。结果IRAB对多黏菌素B敏感,对头孢哌酮/舒巴坦耐药率46.7%,对其他抗菌药物耐药率高于ISAB,差异有统计学意义(P<0.05)。70.0%IRAB外排泵表型阳性,而ISAB全阴性。基因检测显示IRAB的adeB阳性率和相对表达量均高于ISAB,差异有统计学意义(P<0.05)。DNA重组证实,将adeABC-RS基因导入ISAB中,亚胺培南MIC提高64~128倍。结论IRAB往往表现为多重耐药,AdeABC外排泵是导致其耐药的重要原因。

Objective To investigate the role of AdeABC efflux pump in the resistance to imipenem of Acinetobacter baumannii.Methods Thirty isolates of Imipenem-resistant Acinetobacter baumannii(IRAB)and imipenem-sensitive Acinetobacter baumannii(ISAB)were collected,respectively.Minimum inhibitory concentrations(MIC)of anti-microbial agents were detected by an agar dilution method.Efflux pump phenotype was detected by adding efflux pump inhibitor PAβN.The positive rate and relative expression of adeB gene were detected by PCR and RT-qPCR,respectively.AdeABC-RS gene was transfered into adeB-negative ISAB by using of DNA recombination technique.MIC were detected with or without DNA recombination.Results All IRAB were sensitive to polymyxins B and the resistance rate to cefoperazone/sulbactam was 46.7%.The resistance rate to other antibiotics was significantly higher than that in ISAB.The efflux pump phenotype in seventy percent of IRAB were positive,while ISAB were all negative.The adeB positive rate and relative expression of IRAB were significantly higher than those of ISAB.It displayed that MIC to imipenem increased 64-128 times when adeABC-RS gene was introduced into ISAB by DNA recombination.Conclusions IRAB is often resistant to a variety of antibiotics.AdeABC efflux pump is an important cause leading to its resistance.