北京发现ST4821克隆群B群脑膜炎奈瑟菌

Detection of Neisseria meningitidis serogroup B belonging to ST4821 complex in Beijing

目的对2013年1月北京市1例流行性脑脊髓膜炎(流脑)死亡病例标本进行脑膜炎奈瑟菌检测,了解感染病原及分离菌株的分子流行病学特征。方法对患者脑脊液标本进行细菌分离培养,通过常规细菌学试验对分离菌株进行脑膜炎奈瑟菌鉴定、实时荧光定量-聚合酶链反应(real-time fluorescence quantitative PCR)方法检测患者脑脊液和抗凝血中脑膜炎奈瑟菌核酸,同时对鉴定的菌株进行多位点序列分型(MLST)分析、外膜蛋白PorA分型和FetA分型,以及体外药物敏感试验。结果从患者脑脊液和抗凝血标本中均检测到脑膜炎奈瑟菌种特异基因ctrA和血清群B特异基因siaD。从患者脑脊液中分离到1株可疑阳性菌,经实验确诊为B群脑膜炎奈瑟菌。PorA为P1.20,23-9,FetA为F1-91;多位点序列分型分析显示基因型为ST10051,属于ST4821序列群。该菌株对复方新诺明为中等耐药,对环丙沙星和四环素耐药,对青霉素、头孢噻肟、头孢曲松、左氧氟沙星、美罗培南、氯霉素、利福平等药物均敏感。从密切接触者咽拭子中未分离到脑膜炎奈瑟菌。结论该菌株经鉴定为B:P1.20,23-9:F1-91:ST10051(ST4821序列群)。北京地区人群中已经存在高致病性ST4821克隆群B群脑膜炎奈瑟菌,并引发死亡病例,提示应全面掌握本地区脑膜炎奈瑟菌健康人群携带情况及病例菌株分子流行病学资料,为流脑的预防控制提供实验室数据支撑。

Objective To understand the etiological and molecular epidemiological characteristics of a death case of meningococcal disease in Beijing in January 2013. Methods Cerebrospinal fluid （CSF） and blood samples were collected from the case for pathogen isolation. The isolated strain was detected with real-time fluorescence quota polymerase chain reaction （PCR） and multi locus sequence typing （MLST）. Outer membrane protein PorA, FetA genes were detected to identify the isolated strain. Drug susceptibility test to 12 antibiotics was conducted. Results Specific gene ctrA of N. meningitidis and serogroup B-specific gene siaD were detected from the CSF and blood samples. One strain of N. meningitidis was isolated from CSF and no N. meningitidis strains were isolated from throat swabs of the close contacts. The isolate belonged to serogroup B according to bacteriologocal and serological detection results, which was supported by the results of PCR. The MLST analysis indicated that the sequence type of the isolate from the case was ST10051, belonging to ST4821 complex. The PorA and FetA alleles of the strain were P1.20,23 -9 and F1 -91 respectively. The strain was sensitive to 9 antibiotics except for tfimethoprim-sulfamethoxazole, ciprofloxacin and tetracycline. Conclusion The isolate reported had a phenotype of B ： P1.20, 23 - 9 ： F1 - 91 ： ST-10051 （ cc4821 ） which is high pathogenic and had caused infection even death. It is necessary to fully understand the carriage and infection status of N. meningitidis in Beijing.