湖南省C群及W135群脑膜炎奈瑟菌的流行病学及病原学特征分型

Epidemiological and etiological characteristics of serogroup C and serogroup W135 Neisseria meningitidis in Hunan Province

目的了解湖南省C群和W135群脑膜炎奈瑟菌的流行病学及病原学特征。方法收集2006—2016年湖南省流行性脑脊髓膜炎患者的血液或脑脊液、患者密切接触者以及健康人群的咽拭子标本中分离到的脑膜炎奈瑟菌菌株,进行生化检测、血清学分群。选取其中的C群和W135群部分菌株进行药敏试验,并采用脉冲场凝胶电泳(PFGE)分型以及多位点序列分型(MLST)方法对菌株进行分子分型,分析其流行病学特征。结果经生化和血清学确认后,选取22株C群脑膜炎奈瑟菌和9株W135群脑膜炎奈瑟菌进行药敏试验,结果显示对大部分检测抗菌药物全部敏感,但对复方磺胺甲口恶唑C群菌株全部耐药,而W135群菌株的耐药率为55.56%,两者比较差异有统计学意义(χ~2=7.61,P=0.006)。经PFGE分型后,22株C群脑膜炎奈瑟菌共分为5种PFGE带型,其中5株HNC-01带型和13株HNC-02带型属同一亚型;2006年湖南省第1例C群患者分离菌株的PFGE带型为HNC-02,与2012、2013年患者以及患者密切接触者分离菌株的图谱完全一致,与带型为HNC-01的2008、2010、2013年的患者分离菌株仅有一个带型的差异,均属于优势带型。9株W135群脑膜炎奈瑟菌PFGE分型后共分为2个带型,其中首例患者与2013、2016年患者分离菌株的带型一致,均为HNW-01型。选取其中优势带型菌株经MLST后,结果 C群脑膜炎奈瑟菌为ST4821型,W135群脑膜炎奈瑟菌为ST11型,均属于脑膜炎奈瑟菌的高致病性克隆群。结论湖南省C群流脑和W135群流脑自首例病例出现后,各自都成为了该群病例的优势流行克隆群,C群流脑近年有减少态势,但出现了新的流行型别;W135群自2012年起成为我省新的流脑流行株,其优势菌株与国际上侵袭性的W群分型一致,可能引起新的大流行,应及时制定相应的防控政策。

Objective To understand epidemiological and etiological characteristics of serogroup C and W135 Neisseria meningitidis(Nm)in Hunan Province.Methods Nm strains isolated from blood or cerebrospinal fluid of patients with epidemic cerebrospinal meningitis,as well as throat swab specimens of close contacts of patients and healthy people in Hunan Province from 2006 to 2016 were collected,strains were performed biochemical testing and serological grouping.Partial strains of serogroup C and serogroup W135 were selected to perform antimicrobial susceptibility testing,and perform genotyping by pulsed-field gel electrophoresis(PFGE)and multilocus sequence ty-ping(MLST),epidemiological characteristics were analyzed.Results After being confirmed by biochemical and serological detection,22 strains of serogroup C Nm and 9 strains of serogroup W135 Nm were selected to perform antimicrobial susceptibility testing,results showed that all strains were sensitive to most detected antimicrobial agents,but serogroup C Nm were all resistant to compound sulfamethoxazole,resistance rate of serogroup W135 Nm was 55.56%,difference was statistically significant(χ2=7.61,P=0.006).After PFGE typing,22 strains of serogroup C Nm were divided into 5 PFGE bands,HNC-01 band of 5 strains and HNC-02 band of 13 strains were of the same subtype;PFGE band of first isolated strain of serogroup C in Hunan Province in 2006 was HNC-02,which was identical with strains isolated from patients and close contacts of patients in 2012 and 2013,there was only one band that was different from band HNC-01 in strains isolated from patients in 2008,2010,and 2013,all were dominant bands.9 strains of serogroup W135 Nm were divided into 2 band patterns after PFGE typing,the strain from the first patient was the same type as the strains isolated from patients in 2013 and 2016,all were HNW-01 type.Dominant strains were selected for MLST,results showed that serogroup C Nm was ST4821 type,serogroup W135 was ST11 type,all were highly pathogenic clones of Nm.Conclusion After the first case of serogroup C and serogroup W135 epidemic meningitis appeared in Hunan Province,both became the dominant epidemic clone group of the disease,serogroup C Nm decreased in recent years,but new epidemic types have emerged.Serogroup W135 became new epidemic strain of epidemic cerebrospinal meningitis in this province since 2012,the dominant strain is consistent with the globally invasive serogroup W,which may cause a new pandemic,corresponding prevention and control policy should be formulated timely.