泛耐药鲍氏不动杆菌外排泵系统与耐药机制的关系

Relationship between efflux pump and drug resistance mechanism of pandrug-resistant Acinetobacter baumannii

目的探讨外排泵adeABC、IJK、FGH在医院泛耐药鲍氏不动杆菌(PDRAB)中的分布特点及其在耐药机制中的作用。方法收集医院2011年1月-2014年4月临床分离的PDRAB 67株(泛耐药组)及同期非多药耐药鲍氏不动杆菌68株(相对敏感组),用CCCP抑制试验对以上两组进行外排泵表型检测;同时PCR扩增外排泵基因adeABC、IJK、FGH,对产物进行测序,通过琼脂糖凝胶电泳观察结果,比较并分析两组间外排泵差异。结果两组共筛选出外排泵表型阳性菌88株,其中泛耐药组52株占77.6%,相对敏感组36株占52.9%;泛耐药组中adeB、adeG基因检出阳性率为100.0%,adeJ基因阳性率为92.5%;相对敏感组中adeB、adeJ、adeG基因检出阳性率分别为44.1%、75.0%、82.4%;泛耐药组检出阳性率均显著高于相对敏感组(P<0.01);泛耐药组中3种基因同时检出率显著高于相对敏感组(P<0.01)。结论外排泵阳性菌株在鲍氏不动杆菌临床分离株中广泛存在,PDRAB表达率显著增高,外排泵基因adeABC、IJK、FGH在PDRAB中均有高检出率,主动外排泵机制可能在PDRAB的耐药机制中起作用,且与3个基因的共同存在和共同表达有关。

OBJECTIVE To explore the distribution of efflux pumps （adeABC ,IJK ,FGH） in the pandrug‐resist‐ant A cinetobacter baumannii （PDRAB ） and observe the effects on the drug resistance mechanisms .METHODS From Jan 2011 to Apr 2014 ,totally 67 clinical PDRAB isolates were chosen as the pandrug‐resistant group ,mean‐while ,68 strains of non‐multidrug‐resistant Acinetobacter baumannii were assigned as the relatively sensitive group .The phenotypes of the efflux pumps of the two groups were detected by using CCCP inhibition test ,the ef‐flux pumps genes （adeABC ,IJK ,FGH） were amplified by using PCR ,the products were sequenced ,the results were observed by means of agarose gel electrophoresis ,and the differences of the efflux pumps were observed and compared between the two groups .RESULTS A total of 88 strains of PDRAB positive for the efflux pumps were screened out in the two groups ,of which 77 .6% （52 strains ） were screened out from the pandrug‐resistant group ,and 52 .9% （36 strains ） were screened out from the relatively sensitive group .The positive rates of detec‐tion of adeB and adeG genes were 100 .0% in the pandrug‐resistant group ,and the positive rate of adeJ gene was 92 .5% ;the positive rates of detection of adeB ,adeJ ,and adeG were respectively 44 .1% ,75 .0% ,and 82 .4% in the relatively sensitive group ,and the positive rates of detection of the pandrug‐resistant group were significantly higher than those of the relatively sensitive group （P〈0 .01）;the rates of simultaneous detection of the three gen‐otypes of the pandrug‐resistant group were significantly higher than those of the relatively sensitive group （P〈0 .01） .CONCLUSION The efflux pump‐positive strains are prevalent among the clinical isolates of A .baumannii , the expression rate of PDRAB is significantly increased ,and the detection rates of the efflux pump genes （ade‐ABC ,IJK ,FGH） are highly in the PDRAB .The active efflux pump mechanism may play a role in the drug re‐sistance mechanism of the PDRAB ,which is associated with the coexistence and co‐expression of the three genes .