庆大霉素耐药阴沟肠杆菌16S rRNA甲基化酶基因的研究

The study of 16S rRNA methylase genes in Enterobacter cloacae

目的了解庆大霉素耐药阴沟肠杆菌中16S rRNA甲基化酶基因的分布情况。方法筛选临床分离的庆大霉素耐药的阴沟肠杆菌30株。采用聚合酶链反应(PCR)方法扩增16S rRNA甲基化酶五种相关耐药基因armA、rmtA、rmtB、rmtC和rmtD,PCR产物进行电泳分析和测序,抗菌药物的药物敏感性试验采用纸片扩散法进行,Whonet 5.4软件进行数据分析。结果 30株庆大霉素耐药阴沟肠杆菌中16S rRNA甲基化酶基因的检出率为56.7%(17/30),其中30.0%(9/30)检出armA基因、26.7%(8/30)检出rmtB基因,未检出rmtA、rmtC和rmtD基因。30株庆大霉素耐药阴沟肠杆菌对妥布霉素、阿米卡星耐药率分别为93.3%,83.3%;对其他抗菌药物除亚胺培南较敏感外,其余抗菌药物耐药率大于60.0%。结论庆大霉素耐药阴沟肠杆菌中16S rRNA甲基化酶基因主要是armA和rmtB基因,碳青霉烯类对该菌有较好体外抗菌活性。

Objective To investigate the distribution of 16S rRNA methylase genes in gentamicin-resistant Enterobacter cloacae.Method 30 strains of clinically isolated Enterobacter cloacae were collected.Five 16S rRNA methylase genes including armA,rmtA,rmtB,rmtC and rmtD,were detected by polymerase chain reaction（PCR）.The PCR products were confirmed by electrophoresis analysis and sequencing.The Antimicrobial Susceptibility Testing was conducted by disk diffusion method.The data were analyzed by Whonet 5.4 software.Result The relevance ratio of 16S rRNA methylase genes were 56.7%（17/30） including armA genes 30.0%（9/30） and rmtB genes 26.7%（8/30）.None of the isolates carried rmtA,rmtC and rmtD genes.The resistence rate of Enterobacter cloacae to amikacin and tobramycin were 93.3% and 83.3% respectively.While being sensitive to imipenem,the strains were resistant to many other antimicrobial drugs with the resistance rate over 60.0%.Conclusion 16S rRNA methylase genes in Enterobacter cloacae are mainly armA and rmtB genes;Carbapenems has good activity to the isloates in vitro.