耐碳青霉烯类鲍曼不动杆菌对替加环素的耐药机制研究  

Mechanisms of tigecycline resistance in carbapenems-resistant Acinetobacter baumannii strains

作　　者：李梅梅[1] 杜佳[1] 徐春泉[1] 陈华乐[1] 李斌[1] 侯渊博 周铁丽[1] 

机构地区：[1]温州医科大学附属第一医院医学检验中心,325000 [2]温州医科大学检验医学学院,325000

出　　处：《中华微生物学和免疫学杂志》2015年第10期717-722,共6页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金（81171614）;浙江省卫生高层次创新人才培养工程项目（浙卫发[2012]241号）

摘　　要：目的 探讨耐碳青霉烯类鲍曼不动杆菌（ CRAB）对替加环素敏感性降低的机制,为临床医师合理使用抗菌药物和院内感染控制提供理论依据. 方法 应用微量肉汤稀释法检测120株临床分离的CRAB对替加环素的耐药性及外排泵抑制剂CCCP处理前后鲍曼不动杆菌对替加环素的最低抑菌浓度（ MIC）;采用PCR技术扩增外排泵基因adeB、adeJ、adeG、abeM、adeE和外排泵调控基因adeRS以及tetX和tetX1基因;运用实时荧光定量RT-PCR测定adeB、adeJ、adeG和abeM的表达情况.结果 120株CRAB对替加环素的MIC值范围为0.25~8 μg/ml,其中替加环素敏感鲍曼不动杆菌（TSAB）共107株（89.2%）,替加环素非敏感鲍曼不动杆菌（TNAB）共13株（10.8%）. 120株CRAB中adeR和adeJ基因的检出率分别为90.0%和92.5%. adeB、adeS、adeG和abeM基因的检出率均为94.2%. adeE、tetX和tetX1基因均未检出. TNAB与TSAB菌株相比,adeB和adeJ基因表达量分别提高了18.69倍和5.46倍,而adeG和abeM基因表达量无明显提高.在加入10μg/ml CCCP处理后,13株TNAB中8株的MIC下降≥4倍,为外排泵阳性菌株.结论 外排泵系统adeABC和adeIJK可能在我院耐碳青霉烯类鲍曼不动杆菌对替加环素敏感性下降机制中起重要作用,而外排泵系统adeFGH和abeM可能与CRAB对替加环素耐药无关.Objective To investigate the mechanisms of tigecycline nonsusceptibility in carbapen-ems-resistant Acinetobacter baumannii （ CRAB） strains in order to provide a theoretical basis for a reasonable use of antibiotics and the control of nosocomial infection .Methods Susceptibility testing of 120 non-dupli-cate CRAB strains to tigecycline was performed by using the broth microdilution method .Minimal inhibitory concentrations （ MIC） of tigecycline against the A.baumannii strains were determined by using the broth mi-crodilution method before and after exposing the strains to Carbonylcyanide-m-chlorophenylhydrazone （CCCP）, which was the efflux pump inhibitor .Polymerase chain reaction （PCR） was used to amply the ef-flux pumps genes including adeB, adeJ, adeG, abeM, adeE, adeRS, tetX and tetX1.The real-time PCR was performed to measure the expression of efflux pumps genes including adeB, adeJ, adeG, abeM and adeE.Results A total of 120 CRAB strains were collected including 13 （10.8%） tigecycline non-suscep-tible A.baumannii （TNAB） strains and 107 （89.2%） tigecycline susceptible A.baumannii （TSAB） strains.The MIC values of tigecline to the 120 CRAB strains were in a range of 0.25 μg/ml to 8 μg/ml. The adeR and adeJ genes were detected in 90.0%and 92.5%of the 120 CRAB strains, respectively.The positive rates of adeB, adeS, adeG and abeM genes among the 120 CRAB strains were all 94.2%.None of the three genes including adeE, tetX and tetX1 were detected .The mean expression levels of adeB and adeJ in TNAB strains were respectively increased by 18.69 folds and 5.46 folds as compared with those in sensi-tive strains.No significant increase in the expression of adeG and abeM genes was observed in TNAB strains . A 4-fold decrease in the MIC was observed in 8 out of 13 TNAB isolates treated with 10 μg/ml of CCCP .The CCCP could partially reverse the resistance pattern of tigecycline .Conclusion The efflux pump sys-tems of adeABC and adeIJK rather than the abeFGH and abeM systems might play an

关 键 词：鲍曼不动杆菌 替加环素 外排泵 耐药机制 

分 类 号：R446.5[医药卫生—诊断学]