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

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，merE）。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、mere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。

Resistance and genotypes of erythromycin-resistant Streptococcus pneumoniae isolates

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 mefA 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 mef,especially mefE,is also common in S.pneumoniae isolates from Shanghai.