上海市791名健康儿童222株肺炎链球菌携带株研究

Population biology of Streptococcus pneumoniae carried by healthy children in Shanghai

目的 了解健康儿童肺炎链球菌携带株的流行病学特征。方法 测定来自上海 5所幼儿园 (代号分别为JR、PL、SY、WS、ZF) 791名健康儿童鼻咽部分离的 2 2 2株肺炎链球菌健康儿童携带株的耐药谱和血清型 ,并以PFGE、BOXPCR和pbp基因指纹等分子生物学方法分析菌株间亲缘关系。结果 2 2 2株携带株中有青霉素低度耐药株 32株 ,未发现青霉素高度耐药株。全部菌株包括 2 2种血清型 ,常见为 2 3F(2 5 7% )、6A(13 1% )、19F(10 8% )、6B(8 1% )等 ;青霉素低度耐药株包括 8种血清型 ,主要为 2 3F(5 0 % )、19A和 19F(各占 15 6 % )。 32株青霉素低度耐药菌株可分为 8种BOXPCR谱型和 7种PFGE谱型。PFGE谱型A菌株的耐药谱、血清型以及BOXPCR和pbp基因指纹高度一致。自幼儿园SY的儿童分离的肺炎链球菌青霉素耐药率 31 8% ,远高于平均水平 ,该园 2 1株青霉素耐药菌株中 2 0株属于PFGE谱型A或B。结论 上海 5所幼儿园健康儿童肺炎链球菌携带株青霉素耐药率总体尚较低 ,但个别幼儿园具有较高耐药率 。

Objective To investigate the population biology of Streptococcus pneumoniae carried by healthy children. Methods Drug resistant patterns and serotypes of 222 strains were determined. PFGE, BOX PCR and pbp fingerprint techniques were used to analyze the homology among strains. Results Among 222 nasopharyngeal isolates from 5 day care centers, there were 32 penicillin intermediate Streptococcus pneumoniae (PISP,MIC 0.125～1 mg/L), and no penicillin resistant Streptococcus pneumoniae (PRSP,MIC≥2 mg/L) was found. The main serotypes of all strains were 23F(25.7%), 6A(13.1%), 19F(10.8%), and 6B(8.1%). The serotypes of PISP were mainly 23F(50%), 19A(15.6%) and 19F(15.6%).Among the 32 PISP strains, 8 BOX PCR clusters and 7 PFGE types were identified. The resistance patterns, serotypes, BOX PCR and pbp fingerprints of PFGE type A strains were highly consistent. In day care center (DCC) SY, the penicillin resistant rate was 31 8%, being much higher than the average level. Twenty of the 21 PISP strains isolated from this DCC belonged to PFGE type A or B. Conclusions The penicillin resistant rate of Streptococcus pneumoniae carried by healthy children in 5 DCCs of Shanghai was still low. However in one DCC, there could be a prevalence of some resistant clones which resulted in high penicillin resistant rate.