171株儿童侵袭性肺炎链球菌血清分型和多位点序列分型研究

目的了解侵袭性肺炎链球菌在中国儿童中的多位点序列分型(MLST)状况。方法对2006—2008年中国11家儿童医院分离的171株侵袭性肺炎链球菌,采用简易棋盘式肺炎链球菌分型试剂盒进行血清型分型,用聚合酶链反应(PCR)扩增7个看家基因并测序,根据7个基因型的组合确定序列分型(ST)。结果 171株侵袭性肺炎链球菌常见的血清型为19F(19.9%),14(19.3%),19A(18.1%),6B(9.4%)和23F(6.4%),其中有5株(2.0%)用丹麦抗血清无法确定血清型。共检出65种ST,12个克隆群,有1株因未扩增出aroe位点的等位基因无法分型。其中ST320最常见,占17.5%,其次为ST271(13.5%)、ST876(10.5%)。常见的ST同源复合群是CC320(33.9%)和CC876(13.3%)。发现20种新的ST型,已被MLST数据库录入,并有3个新的等位基因序列。结论分离自中国儿童的侵袭性肺炎链球菌主要为ST320、ST271和ST876等3种,流行的克隆群为CC271、CC876。

Serotyping and multilocus sequence typing of 171 isolates from children with invasive pneumococcal diseases

Objective To investigate the distribution of the multilocus sequence typing(MLST)in invasive isolates of Streptococcus pneumonia(SP)from Chinese children.Methods A total of 171 pneumococci isolates were isolated from Chinese children with invasive pneumococcal diseases(IPD)in 11 children’s hospitals between 2006 and 2008.Simplified chessboard system was used for serotyping of SP.Seven house-keeping genes of these isolates were amplified by PCR and sequenced.The sequence type(ST)was determined according to the combination of these 7 genotypes.Results The most common serotypes of 171 pneumococci isolates were 19F(19.9%),14(19.3%),19A(18.1%),6B(9.4%)and 23F(6.4%).There were five strains(2.0%)that cannot be identified with the antisera used.Sixty-five ST types and 12 clonal complexes(CC)were identified.One isolate was unable to typing because of unsuccessful amplification of aroE gene.The most prevalent ST types were ST320(30/171,17.5%),ST271(23/171,13.5%)and ST876(18/171,10.5%).The most common clonal complexes were CC320(33.9%)and CC876(13.3%).Twenty of ST types were new and 3 of allele sequences were identified and have been included into MLST database.Conclusions The most common ST types for SP invasive isolates from Chinese children are ST320、ST271 and ST876.The most prevalent clonal complexes are CC271 and CC876.