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目的了解北京地区儿童中青霉素不敏感肺炎链球菌(PNSP)的流行状况,阐明其分子流行病学特征。方法以2000—2002年于0~5岁上呼吸道感染儿童鼻咽部分离的63株PNSP冻存标本为研究对象,进行耐药模式分析,以聚合酶链反应(PCR)扩增青霉素结合蛋白(PBP)基因pbp1a、pbp2b和pbp2x,分析其限制性片段长度多态性(RFLP),并进行细菌染色体RFLP脉冲场凝胶电泳(PFGE)比较。结果63株PNSP有61株(96.8%)为多重耐药菌株。pbp1a、pbp2b和pbp2x分别有8、9和18种基因型,三者组合的谱型共有30种。63株PNSP的PFGE型共分为35个,其中,9种PFGE型包括菌株≥2株,这9种型共包含37株,占59%,均为多重耐药菌株。与亚洲流行菌株比较,我们发现2株PFGE型可能相关的PNSP分别与亚洲流行菌株越南-19群、新加坡-19群、中国台湾-19群和韩国-19群谱型完全相同。结论北京地区儿童中PNSP的多重耐药状况严峻,克隆传播是PNSP流行的重要因素;已存在与亚洲流行菌株相同的克隆,值得关注。
Objective To understand the prevalence of penicillin-insensitive Streptococcus pneumoniae (PNSP) in children in Beijing and to elucidate its molecular epidemiological characteristics. Methods Sixty-three PNSP frozen samples isolated from the nasopharynx of children with respiratory tract infections aged 0-5 years old from 2000 to 2002 were used as research objects to analyze the drug resistance patterns and amplify the penicillin binding protein by polymerase chain reaction PBP) gene pbp1a, pbp2b and pbp2x were amplified by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP) was analyzed and comparison of bacterial chromosome RFLP pulsed field gel electrophoresis (PFGE) was performed. Results 63 strains of PNSP 61 (96.8%) were multidrug-resistant strains. There are 8, 9 and 18 genotypes for pbp1a, pbp2b and pbp2x, respectively. There are 30 genotypes in all three combinations. Sixty-three PNSP PFGEs were divided into 35 groups, of which 9 PFGEs included more than 2 strains. These 9 strains contained 37 strains (59%), all of which were multi-drug resistant strains. Compared with the Asian endemic strains, we found that two strains of PNGE possibly related to PFGE type were identical to those of the Asian epidemic strains Vietnam -19, Singapore -19, China Taiwan -19 and Korea -19, respectively. Conclusion The multi-drug resistant status of PNSP in children in Beijing is severe. Clonal transmission is an important factor in the prevalence of PNSP. Clones that have the same epidemic strain as Asia exist.