江西省2005-2015年脑膜炎奈瑟菌血清分型和分子分型分析

Serogroup distribution and characteristics of molecular subtyping for Neisseria meningitidis isolated from Jiangxi,2005—2015

目的对江西省2005-2015年分离的脑膜炎奈瑟菌(Neisseriameningitidis,Nm)进行血清分型和分子分型研究,揭示菌群特征和变迁情况。方法对2005-2015年分离的200株脑膜炎奈瑟菌采用血清凝集的方法鉴定血清群,对引起流脑流行的血清群进行脉冲场凝胶电泳(Pulsed Field Gel Electrophoresis,PFGE)和多位点序列分型(Multilocus Sequence Typing,MLST),使用BioNumerics软件构建最小生成树。分析不同来源、不同年份分离株的血清型和分子型别以及变迁情况。结果 200株脑膜炎奈瑟菌中,有168株可鉴定为已知血清群,包括C群(101株)、B群(50株)、A群(12株)、W135群(2株)、Y群(2株)和X群(1株),另外32株为不可分群菌株。临床病人、密切接触者和健康人群分离株中分别有100%、86.0%和28.9%的菌株为C群。针对健康人群分离株,2005年、2007年、2008年、2012年分离的菌株中,C群分别占1.9%、58.8%、81.5%和0%。95株C群菌株分为14个PFGE型,其中NMNh.JX0001和NMNh.JX0002为优势带型,分别包含46和30株菌。NMNh.JX0001型菌株在2005-2006年、2007-2008年、2013-2014年3个时间段在C群菌株中所占比例分别为97.2%、28.6%、10.0%;而NMNh.JX0002型菌株在2005-2006年、2007-2008年、2013-2014年3个时间段在C群菌株中所占比例分别为2.8%、57.1%、90.0%。挑选优势带型以及相似带型的33株菌株进行MLST分型,均为ST-4821型。结论江西省2005-2015年的流脑病例均为C群菌株引起。在健康人群中存在C群脑膜炎奈瑟菌。虽然近10年流行的C群菌株MLST序列型未发生改变,但是PFGE型别发生了变迁,提示菌株基因组存在微进化。PFGE型别的变迁有可能导致流行模式发生改变,所以有必要开展持续监测,密切关注新型菌株在人群中的传播扩散以及引起的流脑病例。

We analyzed the serogroup distribution and molecular subtyping characteristics of Neisseria meningitidis isolated from Jiangxi during 2005 and 2015,and revealed the characteristics and change of population structure.A total of 200 N.meningitides isolated during 2005 and 2015 were investigated by serogroup,pulsed field gel electrophoresis(PFGE)and multilocus sequence typing(MLST).Clustering tree and minimum spanning tree was constructed by using BioNumerics software.The distribution of serogroup and molecular subtypes isolated in different sources and years were analyzed.Among the 200 N.meningitidis,the serogroup were C(101),B(50),A(12),W135(2),Y(2),X(1),non-groupable(32).There were 100%,86.0%and 28.9%of the clinical,close contact and healthy carried isolates were serogroup C.Among healthy carried isolates,there were 1.9%,58.8%,81.5%and 0%of the strains isolated from 2005,2007,2008 and 2012 were serogroup C.The 95 serogroup C strains were isolated into 14 PFGE types and among them NMNh.JX0001 and NMNh.JX0002 were dominant types,including 46 and 30 strains respectively.Among the serogroup C strains isolated during 2005-2006,2007-2008 and 2013-2014,proportion of NMNh.JX0001 strains were 97.2%,28.6%and 10.0%respectively,and proportion of NMNh.JX0002 strains were 2.8%,57.1%,90.0%.Thirty-three serogroup C strains with dominant PFGE types were analyzed by MLST and all were ST-4821.All the meningococcal diseases in Jiangxi between 2005 and 2015 were caused by serogroup C strains.Serogroup C strains have also existed in healthy population.Although the dominant ST of serogroup C has not changed in the past 10 years,the PFGE types have been changed,suggesting that the genome of bacteria exists microevolution.This microevolution might cause the change of epidemic model.Continuous monitoring is necessary.