摘要目的 了解广东省历年流行性脑脊髓膜炎(流脑)病原体的外膜蛋白编码基因porA和porB基因特征,并确定病原体的优势克隆型.方法 对1967-2007年从流脑患者分离的18株脑膜炎奈瑟球菌(Neisseria meningitidis)进行复苏培养和生化鉴定;通过DNA序列测定分析外膜蛋白编码基因porA、porB特征;对菌株进行多位点序列分型(multilocus sequence typing, MLST),采用PHYLIP软件制作进化树,并与脑膜炎余瑟球菌MIST全球数据库(PubMLST)中的菌株比较,确定优势克隆型菌株,探讨广东省历年流脑疫情分离株的看家基因序列多态性.结果 porA可变区(VR)1的型别以20型为主,VR2的型别在2004年前主要为9型,以后呈现多态性;porB可变区Ⅰ、Ⅳ、Ⅴ、Ⅵ主要分别为4、7、11、10型,2004年后可变区Ⅴ、Ⅵ型别增多;除2007年分离的1株W135菌株外,其余菌株的porB基因均无Ⅶ、Ⅷ可变区.在7个看家基因中,abcZ等位基因多态性最低,pgm最高.广东省历年流行性脑脊髓膜炎分离株2004年前的优势克隆为ST-5克隆系,自2004年开始出现高致病性ST-4821克隆系,2007年首次出现高致病性ST-11克降系.结论 广东省历年脑膜炎奈瑟球菌分离株的外膜蛋白编码基冈呈现多态性特征,分离株为多克隆系并存,近期以高致病性克隆系为主.

abstractsObjective To study the molecular characters of porA and porB genes which encode outer membrane proteins (OMP), and predominated clonal complex of Neisseria meningitidis isolates from Guangdong province. Methods Eighteen Neisseria meningitidis isolates from Guangdong province during year 1967 to 2007 were recovered and reconfirmed by API NH biochemical system, and serogrouped by antiserum. The characters of porA and porB gene were analyzed by DNA sequencing. The allele profiles and the sequence types (ST) were determined by multilocus sequence typing (MLST). Based on their allelic profiles, the evolution relationship was analyzed by PHYLIP software. The predominant clonal complex was determined through comparing with the information of reference strains from the PubMLST database. Results For porA gene, type 20 was more frequently in the variable region (VR) 1 and type 9 in VR2 before year 2004. However, for porB gene, type 4 was more frequently in VR Ⅰ, type7 in VR Ⅳ, type 11 in VR Ⅴ,and type 10 in VR Ⅵ, respectively. The multi-types character was presented in VR Ⅴ and VR Ⅵ after2004. VR Ⅶ and VR Ⅷ can not be found among all the isolates except for one W135 isolate in 2007. Among the seven housekeeping genes, the polymorphism of abcZ was the lowest one with 4 allele numbers, while pgm was the highest one with 13 allele numbers. The predominant clonal complex was ST-5 before 2004. The ST-4821 clone complex appeared in 2004 and caused cases every year since then. More important, highly invasive ST-11 clonal complex firstly appeared in Guangdong in 2007. Conclusion The molecular characteristic of OMP genes presents polymorphism for the Neisseria meningitidis isolates from patients in Guangdong province during 1967 to 2007. ST-5 is the predominant clonal complex before 2004 and the highly invasive clonal complex is circulating in recent 3 years. It suggests that the surveillance based on laboratory should be further enhanced.