摘要
目的探讨主动外排系统AcrAB在大肠埃希菌耐碳青霉烯类药物中的作用,为临床抗感染治疗提供理论参考。方法采用琼脂平板倍比稀释法测定抗菌药物对20株碳青霉烯耐药大肠埃希菌的最低抑菌浓度(MIC),采用改良Carb NP法检测细菌产碳青霉烯酶类型,实时荧光定量PCR(RT-PCR)检测碳青霉烯酶阴性和阳性菌株acrAB基因表达的差异及亚-MIC亚胺培南(IMP)对碳青霉烯酶阴性菌株acrAB基因表达的影响。结果碳青霉烯耐药大肠埃希菌除对阿米卡星敏感率较高外,对其他抗菌药物均有较高的耐药性。产酶实验和PCR扩增结果显示,共有8株菌携带NDM-1基因,3株携带IMP-4基因,1株携带KPC-2基因,此外有1株菌产酶而PCR扩增阴性。RT-PCR结果显示,碳青霉烯酶阴性菌株的acrAB基因表达水平明显高于阳性菌株,且亚-MIC IMP能明显诱导碳青霉烯酶阴性菌株的acrAB基因表达(P<0.05)。结论主动外排系统Acr AB是大肠埃希菌对碳青霉烯类药物耐药的重要影响因素。
Objective To investigate the role of active efflux system AcrAB in carbapenem-resistant Escherichia coli,and provide theoretical references for clinical anti-infective therapy.Methods The minimum inhibitory concentration(MIC)of antibacterial drugs against 20 carbapenem-resistant Escherichia coli was determined by agar plate dilution method.The carbapenemase type was detected by modified Carb NP method.The differences of acrAB gene expression in carbapenemase-negative and-positive strains,and the effect of sub-MIC imipenem on acrAB gene expression of carbapenemase-negative strains were determined by Real-Time PCR(RT-PCR).Results Except for amikacin,carbapenem-resistant Escherichia coli had high resistance to other antibiotics tested.The results of carbapenemase screening and PCR amplification showed that eight strains carried the NDM-1 gene,three strains carried the IMP-4 gene,and one strain carried the KPC-2 gene.Moreover,there was one carbapenemase-producing strain which didn't carry resistance genes.The RTPCR results showed that the expression of acrAB gene in carbapenemase-negative strains was higher than that of positive strains.Sub-MIC imipenem could significantly induced acrAB gene expression in carbapenemasenegative strains(P<0.05).Conclusion The active efflux system AcrAB is an important factor in the resistance of Escherichia coli to carbapenems.
作者
洪海
冯伟
李燕
曲欣
孙凤军
HONG Hai;FENG Wei;LI Yan;QU Xin;SUN Fengjun(Outpatient Department,the 15th Retired Cadre Recuperation of Beijing Weishu District,Beijing 100141,China;Department of Pharmacy,the First Hospital Affiliated to AMU,Chongqing 400038,China)
出处
《重庆医学》
CAS
2019年第24期4147-4150,共4页
Chongqing medicine
基金
国家自然科学基金面上项目(81373451)
