江西省脑膜炎奈瑟菌分离株分子分型和菌群结构分析

Analysis of molecular subtypes and microflora structure of Neisseria meningitidis strains isolated inJiangxi province

目的分析江西省脑膜炎奈瑟菌（Neisseriameningitidis，Nm）分离株的分子分型和菌群结构。方法选取于1976-1987年和2005-2008年在江西省分离自患者、密切接触者和健康人群的123株Nm菌株作为研究对象。采用多位点序列分型（MLST）、外膜蛋白编码基因proAPCR扩增并测序等方法，检测Nm基因型特征及porA的序列特征。使用BioNumerics软件构建最小生成树，分析菌株菌群结构。结果1976-1987年分离67株Nm菌，血清群分布为A群（43株）、B群（18株）、C群（1株）和W135群（5株）；2005-2008年分离56株Nm菌，血清群分布为A群（3株）、B群（7株）、C群（45株）和不可分群（1株）。123株Nm菌株分为40个序列（ST）型，46株A群菌株分为14个ST型，以ST-3型为优势型别，共29株菌，占A群菌株的63．0％（29／46），分离于1976年至1987年，分离自患者（14株）、密切接触者（9株）、健康人群（6株）；46株C群菌株分为5个ST型，以ST-4821为优势型别，共41株，占89．1％（41／46），分离于2005年至2008年，分离白患者（6株）、密切接触者（6株）、健康人群（29株）。123株Nm菌株的porA基因分属于32个不同的型别，包含了24个不同VRI型和22个VR2型。1976—1987年的流行菌株为ST-3型A群Nm，PorA分型为P1．7-1，10，为优势型别，菌株数为18株，占A群Nm的39．1％（18／46），分离自患者（11株）、密切接触者（4株）、健康人群（3株）；2005-2008年的流行菌株为ST-4821型c群Nm，PorA分型2005年以P1．20，9为主，共19株，占ST-4821型c群Nm流行菌株的46．3％（19／41），分离自密切接触者（1株）、健康人群（18株）；2006年开始以P1．7-2，14型为主，共22株，占ST-4821型C群Nm流行菌株53．7％（22／41），分离自患者（6株）、密切接触者（5株）、健康人群（11株）；B群菌株不存在优势序列群，呈多型性特点；W135群菌株5株均为ST-174序列群，PorA分型为P1．21，16，分离于1979年至1980年，分离白密切接触者（3株）、健康人群（2株）。结论江西省Nm分离株具有基因多态性，同时也存在优势克隆群，在不同时期存在不同的流行克隆；流行克隆已由A：ST-3：P1．7-1，10变迁为C：ST-4821：P1．7-2，14。

Objective To study the molecular subtypes and microflora structure of Neisseria meningitidis （Nm） strains isolated in Jiangxi province. Methods A total of 123 Nm strains separately isolated from patients,close contacts and health people in 1976 - 1987 and 2005 -2008 were investigated by muhiloeus sequence typing （MLST） and PorA subtyping,to test the characteristics of gene Nm and sequence porA. Minimum spanning tree was constructed by using BioNumefics software based on data of MLST; and the microflora structure was then analyzed. Results The serogroups of 67 Nm strains isolated in 1976 - 1987 included group A （43 strains） ,group B （18 strains） ,group C （1 strains） and group W135 （5 strains） ; while the serogroups of 56 Nm strains isolated in 2005 -2008 included group A （3 strains）, group B （7 strains）, group C （45 strains） and 1 ungrouped strain. The total 123 Nm strains could be divided into 40 MLST types;while the 46 strains in group A could be divided into 14 MLST types,29 out of which belonged to ST-3 type, accounting for 63.0% （29/46） as the dominant type. All of the 29 strains were isolated between 1976 and 1987,while 14 strains were isolated from patients,9 were from close contacts and 6 were from health people. The 46 strains in group C could be divided into 5 MLST types,41 out of which belonged to ST-4821 type,accounting for 89. 1% （41/46）. All of the strains were isolated between 2005 and 2008,6 strains were isolated from patients ,6 were from close contacts and 29 were from health people. The porA gene of the total 123 Nm strains were classified to 32 different types, including 24 different VR1 types and 22 different VR2 types. The dominant PorA type of the prevalent strain （ST-3 type, group A） between 1976 and 1987 was P1.7-1,10,accounting for 39. 1% （18/46） of the strains in group A; while the 18 strains were isolated from 11 patients,4 close contacts and 3 health people. The dominant PorA type of the prevalent strain （ ST-4821 type ,group C） between 2005 and 2008 was PI. 20,9 ,accounting for 46. 3% （ 19/41 ） of the ST-4821 strains in group C; while the 19 strains were isolated from 1 close contacts and 18 health people. P1.7-2,14 dominated since 2006,including 22 strains, accounting for 53.7% （ 22/41 ） of the ST-4821 strains in group C, isolated from 6 patients ,5 close contacts and 11 health people. There were no dominant PorA type found in group B and all the 5 strains in group W135 belonged to ST-174 and the PorA type was P1.21,16, isolating from 3 close contacts and 2 health people between 1979 and 1980. Conclusion Nm isolated in Jiangxi province showed significant gene polymorphism, as well as predominant lineages existing. In different periods, the prevalent lineages varied a lot, as translating from serogroup A ： ST-3 ： P1.7-1,10 to serogroup C ： ST-4821 ： P1.7-2,14 nowadays.