儿童鼻咽部肺炎链球菌携带株研究

Population biology of Streptococcus pneumoniae carried by healthy children

目的了解武汉地区健康儿童肺炎链球菌带菌状况、耐药性、耐药基因及血清型流行情况。方法收集武汉地区2所幼儿园469名健康儿童的鼻咽拭子标本,分离鉴定肺炎链球菌,琼脂稀释法测定其对12种抗菌药物的MIC;PCR检测红霉素耐药基因ermB和mefA;“荚膜肿胀”试验进行血清学分型。结果469份鼻咽拭子标本共分离出116株肺炎链球菌,分离率为24.7%。存活的114株中,肺炎链球菌对青霉素的敏感率为51.8%(59/114),对红霉素的敏感率为13.2%(15/114)。99株红霉素耐药肺炎链球菌中,ermB基因总检出率为98.0%(97/99),其中30株(31.6%)同时具有ermB和mefA基因,2株红霉素低耐株仅检出mefA基因。血清分型涉及16个血清型、群,主要分布在19、23、6和14血清群。结论武汉地区肺炎链球菌耐药性高,多为多重耐药菌株,红霉素耐药基因主要为ermB,19、23、6血清群多重耐药株分布广泛。

Objective To investigate the population biology of Streptococcus pneumoniae carried by healthy children in Wuhan. Methods A total of 116（114 available） strains of S. pneumoniae were isolated from 469 children to determine the susceptibility to 12 antimicrobial agents. Primers for ermB and mefA were used to amplify ermB and mefa genes. Bacterial homology was analyzed in terms of serotypes and antibiotic resistant patterms. Results Among the 114 nasopharyngeal isolates from two daycare centers, 59（51.8 % ） penicillin-susceptible and 15 （ 13.2 % ） erythromycin-susceptible S. pneumoniae were identified. The ermB gene was identified in 98.0% （97/99） of the erythromycin-resistant strains, including 30 strains（30.3%） contained both ermB and mefa genes, mefa alone in 2.0% （2/99） of erythromycin-resistant strains. Sixteen serotypes were characterized in the 114 strains. The prevalent serotypes were 19 （26.3%）, 23 （24.6%）, 6 （17.5%）and 14 （6.1%）. Five （4.4%） strains were non-typable. Conclusions The antibiotic resistance of S. pneumoniae is serious in Wuhan. Most of the strains were multi- resistant, ermB gene was main mechanism of erythromycin resistance in S. pneumoniae. The prevalent multi-resistant serotypes were types 19, 23 and 6.