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目的探讨耐碳青霉烯类抗生素肺炎克雷伯菌(CRKP)临床分离株中16 S rRNA甲基化酶基因存在情况及同源性。方法收集南昌4家医院29株CRKP,用聚合酶链反应(PCR)扩增耐药基因,确定其基因型。用接合试验评价耐药质粒的可转移性,脉冲场凝胶电泳(PFGE)对其进行同源性分析。结果 29株CRKP临床分离株对阿米卡星和庆大霉素的耐药率分别为37.9%和69.0%。10株16 S rRNA甲基化酶基因阳性菌株,其中9株armA阳性,1株rmtB阳性,对阿米卡星和庆大霉素均耐药,耐阿米卡星的菌株同时耐庆大霉素。10株16 S rRNA甲基化酶基因阳性菌中均同时携带β内酰胺酶基因,其中7株同时携带碳青霉烯酶基因,以KPC-2及NDM-1为主。10株菌株均被PFGE成功分型,分别属于9个不同克隆,3株armA阳性菌通过接合实验成功的把耐药质粒传递给受体菌E.coli J53。结论 CRKP对氨基糖苷类抗生素的耐药性与16S rRNA甲基化酶基因高度有关,且armA是其主要型别。携带16 S rRNA甲基化酶基因的质粒可通过水平播散。
Objective To investigate the presence and homology of 16 S rRNA methylase gene in clinical isolates of carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods Totally 29 CRKPs from 4 hospitals in Nanchang were collected. The resistance genes were amplified by polymerase chain reaction (PCR) and their genotypes were determined. The conjugation test was used to evaluate the transferability of drug-resistant plasmids and their homology was analyzed by pulsed-field gel electrophoresis (PFGE). Results The resistance rates of 29 clinical isolates of CRKP to amikacin and gentamycin were 37.9% and 69.0%, respectively. 10 strains of 16S rRNA methylase gene positive strains, of which 9 were armA positive, 1 rmtB positive, resistant to amikacin and gentamicin, resistant strains of amikacin resistant to mold Prime The 10 strains of 16S rRNA methylase gene-positive bacteria carried both β-lactamase genes, of which 7 also carried carbapenemase genes, mainly KPC-2 and NDM-1. The 10 isolates were successfully genotyped by PFGE and belonged to 9 different clones respectively. Three armA positive bacteria passed the resistant plasmids to E. coli J53 successfully through conjugation experiments. Conclusion The resistance of aminoglycoside antibiotics to CRKP is highly related to the 16S rRNA methylase gene, and armA is the major type. Plasmids carrying the 16S rRNA methylase gene can be disseminated horizontally.