肺炎克雷伯菌整合子分布与耐药性关系

The relationship between the distribution difference of the integron in klebsiella pneumoniae and drug resistance

目的通过调查Ⅰ、Ⅱ、Ⅲ类整合子在临床分离产ESBL与非产ESBL肺炎克雷伯菌中的分布情况,分析其与细菌耐药性关系。方法收集并保存临床送检标本分离出的产ESBLs肺炎克雷伯菌30株,非产ESBLs肺炎克雷伯菌50株;采用BD phoenix100全自动细菌鉴定仪进行鉴定及药敏试验;整合子及可变区测定采用聚合酶链式反应(PCR)扩增和琼脂糖凝胶电泳,并对可变区阳性菌株进行测序分析。结果 80株肺炎克雷伯菌中检测出整合子Ⅰ阳性菌株共30株;其中,在产ESBL菌株中检出率为73.3%(22/30);非产ESBL肺炎克雷伯菌中检出率为16%(8/50);未检出Ⅱ类及Ⅲ类整合子。有8株成功扩增出可变区,检出dfrA1,dfrA12,dfrA17,dfrA25,AaadA1,aadA2,aadA5,orfC,orfF,cmlA1共10种耐药基因盒,与耐药表型有一定的相关性。结论 I类整合子在ESBL和非产ESBL的肺炎克雷伯菌中的分布存在明显差异,显示其与细菌耐药性关系密切,应予以足够重视。

Objective To investigate the distribution of I,II,III integrons in ESBL-producing and non-ESBL-producing Klebsiella pneumonia(KP),exploring the relationship between the drug resistance characteristics and the integrons in our hospital.Methods 30 strains of KP producing ESBLs and 50 strains of non-ESBLs KP were isolated and preserved from clinical specimens.The BD phoenix100 automatic bacteria identification instrument was used for identification and drug susceptibility testing;integrons and variable regions were detected using Polymerase Chain Reaction(PCR)and agarose gel electrophoresis,and variable region were sequenced to clarify the context of gene cassette.Results 30 strains of classs 1 integron-positive strains were detected in 80 strains of KP;among them,the detection rate of that in ESBL-producing strains was 73.3%(22/30);which in non-ESBL-producing strains was 16%(8/50);and no classⅡandⅢintegrons was detected.The variable regions were successfully amplified in 8 strains for classs I integronpositive and 10 drug-resistant gene boxes including dfrA1,dfrA12,dfrA17,dfrA25,AaadA1,aadA2,aadA5,orfC,orfF and cmlA1 were found.There’s some correlation between the gene cassette carried by ingegron with the resistance phenotype.Conclusion The distribution of class I integrons in ESBL and non-ESBL-producing KP is significant.The difference showed that it is closely related to the resistance,which should be paid enough attention.