肺炎链球菌对大环内酯类抗生素耐药情况及耐药基因研究

Resistance and genotypes of erythromycin-resistant Streptococcus pneumoniae isolates

目的调查上海地区肺炎链球菌对红霉素的敏感度,研究肺炎链球菌对大环内酯类抗生素耐药机制。方法对中山医院57株临床分离肺炎链球菌进行红霉素药敏试验;应用聚合酶链反应(PCR)技术对上海4所医院中分离的53株红霉素耐药肺炎链球菌检测耐药基因(ermB,mefA,mefE)。结果57株肺炎链球菌中12株(21.0%)敏感,3株(5.3%)中介,42株(73.7%)耐药。53株红霉素耐药肺炎链球菌中,ermB基因、mefE基因、mefA基因分别在51株(96.2%)、22株(41.5%)和1株(1.9%)中检测到。其中21株(39.6%)同时检测到ermB基因和mefE基因,1株(1.9%)同时检测到ermB基因和mefA基因,1株(1.9%)未检测到ermB基因、mefE基因或mefA基因。结论上海地区肺炎链球菌对大环内酯类抗生素耐药率较高。ErmB介导的靶位改变是最常见的耐药机制,mef(特别是mefE)介导外排机制引起者也较常见。

Objective To investigate the prevalence and genotypic characterization of erythromycin-resistant Streptococcus pneumoniae in Shanghai, China. Methods Fifty-seven strains of S. pneumoniae from Zhongshan Hospital were collected to evaluate the prevalence of antibiotic resistance and 53 strains of erythromycin-resistant S. pneumoniae from 4 hospitals in Shanghai were examined by PCR for the presence of macrolide resistance genes （ermB, mefA and mefE）. Results Of the 57 isolates, 12 （21%） were susceptible, 3 （5.3%） intermediate, and 42 （73.7%） resistant to erythromycin. Of the 53 isolates, 51 （96.2%） were positive for ermB gene, 22 （41.5%） positive for mefE, and 1 （1.9%） positive for mefA gene in PCR study. Both mefE and ermB genes were detected from 21 （39.6%） isolates, both rnefA and ermB genes were detected in 1 isolate. One isolate had none of mefA, mefE or ermB gene. Conclusions Erythromycin resistance in S. pneumoniae is a serious problem in Shanghai, China. Target alteration induced by ermB is the most common mechanism of erythromycin resistance and reef, especially mefE, is also common in S. pneumoniae isolates from Shanghai.