CAJ | 학술논문

目的：明确AdeABC外排系统在亚胺培南获得性耐药鲍曼不动杆菌中的作用。方法用试管二倍稀释法对6株亚胺培南敏感鲍曼不动杆菌进行体外诱导；用琼脂稀释法测定10种抗菌药物及加入外排泵抑制剂氰氯苯腙（ CCCP ）12.5 mg· L-1后菌株的耐药表型。脉冲场凝胶电泳对菌株进行分型。用PCR及测序方法检测相关耐药基因。 Real -time PCR 方法检测菌株 blaAdeB及blaOXA-51-like mRNA表达量变化。结果6株鲍曼不动杆菌为亚胺培南及美罗培南敏感的多药耐药菌株。经亚胺培南体外诱导后，4株菌对亚胺培南的最低抑菌浓度（ MIC）值有4倍以上增加，成为亚胺培南耐药菌株。在加入CCCP后，对亚胺培南及美罗培南的MIC值下降到1/2～1/8。6株菌均携带blaOXA-66基因。blaoxa-23-like、blaoxa-24-like、blaoxa-58-like、blaimp及blavim基因检测均阴性。4株诱导后对亚胺培南耐药的菌株中，3株（H099、R010及T375）blaAdeB表达量增加2～14倍。另外1株K645菌株blaAdeB表达量无增加，blaOXA-51-like表达量增加17倍。2株诱导后亚胺培南MIC值无升高的菌株，其诱导前后blaAdeB及blaOXA-51-like表达量均无增加。结论在对鲍曼不动杆菌临床治疗应当尽量避免亚MIC浓度碳青霉烯类抗菌药物暴露，避免细菌耐药表型变化。 AdeABC外排系统的过表达可能同本实验1株鲍曼不动杆菌对亚胺培南获得性耐药相关。
목적：명학AdeABC외배계통재아알배남획득성내약포만불동간균중적작용。방법용시관이배희석법대6주아알배남민감포만불동간균진행체외유도；용경지희석법측정10충항균약물급가입외배빙억제제청록분종（ CCCP ）12.5 mg· L-1후균주적내약표형。맥충장응효전영대균주진행분형。용PCR급측서방법검측상관내약기인。 Real -time PCR 방법검측균주 blaAdeB급blaOXA-51-like mRNA표체량변화。결과6주포만불동간균위아알배남급미라배남민감적다약내약균주。경아알배남체외유도후，4주균대아알배남적최저억균농도（ MIC）치유4배이상증가，성위아알배남내약균주。재가입CCCP후，대아알배남급미라배남적MIC치하강도1/2～1/8。6주균균휴대blaOXA-66기인。blaoxa-23-like、blaoxa-24-like、blaoxa-58-like、blaimp급blavim기인검측균음성。4주유도후대아알배남내약적균주중，3주（H099、R010급T375）blaAdeB표체량증가2～14배。령외1주K645균주blaAdeB표체량무증가，blaOXA-51-like표체량증가17배。2주유도후아알배남MIC치무승고적균주，기유도전후blaAdeB급blaOXA-51-like표체량균무증가。결론재대포만불동간균림상치료응당진량피면아MIC농도탄청매희류항균약물폭로，피면세균내약표형변화。 AdeABC외배계통적과표체가능동본실험1주포만불동간균대아알배남획득성내약상관。
Objective To evaluate the mechanism of AdeABC efflux pump on induced imipenem resistant Acinetobacter baumannii clinical iso-lates.Methods Six imipenem susceptible A.baumannii isolates were induced by broth dilution method.MICs of 10 antibiotics with carbonyl cyanidem chlorophenylhydrazone ( CCCP ) were tested by agar dilution.The isolates were genotyped by pulsed -field gel electrophoresis ( PF-GE).PCR assays for genes coding for related genes were performed.The levels of blaAdeB and blaOXA-51-like mRNA expressions were tested by real -time PCR assays.Results The six imipenem susceptible A.baumannii isolates were all multidrug resistant.Four isolates exhibited imipenem re-sistantance after induced by imipenem , and MICs of imipenem and mero-penem with CCCP were two to eight times lower.Nucleotide sequencing showed that the blaOXA-66 alleles were detected.PCR for tested genes was negative except the blaOXA-51-like.The levels of blaAdeB mRNA expression in 3 induced imipenem resistant isoaltes increased two to fourteen times than the original isolates , while the isolate ( K645 ) with 17 times in-crease of the expression of blaOXA-51-like mRNA did not show increasing expression of blaAdeB mRNA.Two isolates were still imipenem susceptible after induced by imipenem which expression levels of blaAdeB and blaOXA-51-like mRNA showed no increasing.Conclusion The patients with A.baumannii infection should avoid being exposed to the subinhibitory concentration of carbapenem , to prevent changes of bacterial resistant profiles.AdeABC efflux pump probably contributes to the resistance of imipenem in one tested A.baumannii isolate.