2011年湖北省健康人群C群流行性脑脊髓膜炎血清杀菌力抗体检测分析

目的了解和分析湖北省健康人群中C群流行性脑膜炎奈瑟菌(Nm)抗体的保护性水平。方法随机抽取湖北省8个年龄组共236份健康人群血清样品,采用血清杀菌试验方法,以C群Nm疫苗株(C11)作为杀菌力实验的靶菌,国家流脑标准品测试血清作为参考血清,进行杀菌力检测,应用SAS9.1对检测结果进行统计分析。结果 236份健康人群血清中C群Nm杀菌抗体阳性率为65.68%,几何平均滴度(GMT)为1︰12.69,人群保护率(抗体滴度≥1︰8)为57.20%,其中,<1岁年龄组GMT最低,为1︰1.10,阳性率为6.67%,人群保护率为0;15～19岁年龄组GMT最高,为1︰92.63,阳性率和人群保护率均为96.67%。3岁以下儿童GMT为1︰1.50,阳性率为21.67%,保护率为8.33%。结论湖北省3岁以下年龄组健康人群对C群Nm血清杀菌力水平较低,实施扩大免疫规划后,仍需要采取措施以提高3岁以下儿童C群流脑抗体水平。     

江西省2005-2015年脑膜炎奈瑟菌血清分型和分子分型分析

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。     

河北省B群脑膜炎奈瑟菌药物敏感性及分子分型分析

目的了解河北省分离的9株B群脑膜炎奈瑟菌（Neisseriameningitides，Nm）的药物敏感性及分子流行病学特征。方法对分离菌株进行E—test法药物敏感性试验和多位点序列分型（MultilocusSequenceTyping，MLST）分析。结果药敏试验显示，9株B群Nm均对磺胺类抗生素耐药；6株分离自健康人的Nm中2株对喹诺酮类抗生素耐药；3株分离自流脑病人的Nm中的2株菌株对喹诺酮类抗生素耐药，且对青霉素类抗生素的敏感性降低。显示9株Nm菌株中的6株属于ST-4821克隆群，1株属于ST-175克隆群，2株无相应的克隆群。结论高致病性ST-4821已成为河北省B群Nrn的优势克隆群，提示应加强流脑的病原学监测。     

脑膜炎奈瑟氏菌感染菌群与血清抗体的调查

本文报道了德州地区1973～1979年流行性脑脊髓膜炎(流脑)周期流行中人群脑膜炎奈瑟氏菌感染的菌群和血清抗体的调查资料。作者指出,当前流脑的流行菌株95%以上是A群流脑菌,带菌菌株是以B群占绝对优势。健康带菌具有带菌率高、带菌期长和相对稳定等特点。作者认为,总带菌率与流脑流行无关,而A群带菌率却与流脑的流行趋势基本一致。人群血凝抗体的调查资料表明,流脑多发生于A群血凝抗体基础水平较低的人群中,发病高峰是由于人群对流行菌株普遍易感所致。带菌感染所产生的交叉免疫反应,有防止流脑发病的重要作用。     

乌鲁木齐地区部分健康人群流脑A群、C群抗体水平监测与分析

目的 了解乌鲁木齐市7区1县健康人群A群、C群流行性脑脊髓膜炎(流脑)IgG抗体水平情况.方法 采用酶联免疫吸附试验(ELISA)方法,对525份血清样本进行IgG抗体水平检测.结果 A群流脑抗体总阳性率为26.29%,抗体几何平均滴度(GMT)为1:1.42;仅5～岁组与35～岁组有显著性差异(χ2 =31.82,P<0.01).C群抗体总阳性率为13.33%,GMT为1:1.18.结论 流脑A群、C群获得免疫性较低,平均流脑抗体水平阳性率为39.62%,GMT为1:1.68, 对于防止脑膜炎球菌的感染保护作用低.为提高人群免疫力,建议将A C群脑膜炎球菌多糖菌苗纳入儿童计划免疫程序,并对菌苗接种后的人群进行流脑抗体水平的随防监测.     

新疆阿勒泰市健康人群流行性脑脊髓膜炎抗体水平监测分析

目的了解新疆阿勒泰市健康人群流行性脑脊髓膜炎(简称流脑)A群、C群抗体水平和带菌状况,预测流脑疫情发病趋势,及时采取针对性控制措施。方法按分层随机抽样方法,分7个年龄组在全市采集血样(<1岁、1～2岁、3～4岁、5～6岁、7～14岁、15～19岁、≥20岁),每组随机抽取30人,采集调查者静脉血2 ml,用ELISA法检测不同年龄组人群血清中A群、C群免疫抗体水平,并进行统计分析。结果 210份不同年龄组人群血清流脑抗体测定结果,A群阳性率为62.0%,抗体水平以5～6岁组和7～14岁组最高,分别是83.3%、90.0%;C群阳性率为40.5%,7～14岁组抗体阳性率为70.0%,其余年龄组流脑C群抗体阳性率较低;流脑A群抗体阳性率高于C群。结论阿勒泰市健康人群中流脑A群IgG抗体阳性率维持在中等水平,C群IgG抗体处于较低水平;建议加强流脑疫苗的预防接种工作及监测。0岁组、1岁组A群流脑抗体免疫水平不高,与部分儿童未到接种时间或儿童初始二针接种未完成有关。     

贵州省1例B群流行性脑脊髓膜炎病例的病原学分析

目的对贵州省遵义市2016年4月发现的1例B群流行性脑脊髓膜炎(流脑)病例进行病原学分析。方法采集患者血液标本,分离菌株,进行生化鉴定和血清分型、多位点序列分型(multilocus sequence typing,MLST);采用KB纸片扩散法和Etest法对菌株进行药敏试验。结果从患者血液中分离到的菌株其菌落形态、生化特征均符合脑膜炎奈瑟菌特性,玻片凝集试验和Real-time PCR鉴定其血清型为B群,基因MLST分型为ST-12885型。该菌对青霉素、氨苄西林、头孢噻肟、头孢曲松、阿奇霉素、美罗培南、米诺环素、氯霉素、利福平等抗生素敏感,对复方新诺明、左氧氟沙星、环丙沙星耐药。结论贵州省1例流脑患者血液中首次检出B群脑膜炎奈瑟菌,属ST-4821高致病性克隆群。因此应加强对流脑病原菌的检测,采取有效防控措施,合理使用抗菌药物。     

应用荧光定量PCR检测细菌性脑膜炎病原体DNA的研究

目的应用荧光定量PCR检测细菌性脑膜炎病原体DNA,并对脑膜炎奈瑟菌进行基因分群。方法提取脑膜炎患者脑脊液和血标本中待检菌DNA,采用荧光定量PCR扩增ctrA、bexA、lytA基因,对ctrA扩增阳性标本及部分流脑菌株进行基因分群。结果 685份脑脊液标本中19份检出脑膜炎奈瑟菌、8份检出肺炎链球菌、2份检出b型流感嗜血杆菌DNA基因片段;2份血清标本脑膜炎奈瑟菌DNA基因检测均为阳性。对ctrA基因扩增阳性标本进行A、B、C、W135、X及Y分群,有18份为C群,3份为B群;部分健康人群携带的流脑菌株有14份为B群,2份为C群,1份为X群。结论荧光定量PCR灵敏性高,检测快速,可用于细菌性脑膜炎病原体的检测、鉴别及对脑膜炎奈瑟菌的分群。     

一起学校流行性脑脊髓膜炎暴发疫情的病原学鉴定及其MLST分型分析

目的报告一起学校流行性脑脊髓膜炎（流脑）暴发疫情的病原学鉴定及病原学特征。方法对疑似流脑病例进行流行病学调查;采集患者血和脑脊液标本,进行实时荧光定量PCR检测,对分离菌株进行生化鉴定并进行E—test法药敏试验和多位点序列分型（multilocus sequence typing,MLST）分析。结果此疫情由C群脑膜炎奈瑟菌引起,分离菌株对磺胺甲基异嗯唑、环丙沙星、萘啶酸耐药。MLST分析该菌为ST-9792型,属于ST4821高致病克隆群。结论该起流脑疫情由C群脑膜炎奈瑟菌ST-9792型引起,确诊病例数多。提示应加强对当地流脑的监测,在流行季节开展人群C群流脑疫苗接种。     

65例流行性脑脊髓膜炎患者的临床特征及流行病学分析

目的 总结2003年以来合肥流行性脑脊髓膜炎(流脑)的临床特征,为今后的流脑防治工作积累经验.方法 对65例流脑患者的临床资料进行凹顾性分析,统计分析采用卡方检验.结果 患者主要集中在青少年和成人,分别为29例(44.6%)和23例(35.4%),婴幼儿最少,仅4例(6.2%).临床分型以普通型为主,占72.3%,暴发型占27.7%,死亡5例(7.7%).共分离出33株脑膜炎奈瑟菌,培养阳性率为50.8%(33/65例),其中,血培养阳性率为44.6%(29/65例),脑脊液培养阳性者占31.4%(16/51例).药物敏感结果显示,无论是C群脑膜炎奈瑟菌还是其他群,对青霉素、头孢曲松、头孢噻肟等普遍敏感,而对复方磺胺甲(噁)唑、庆大霉素、环丙沙星等耐药率都在80%以上.血清学分类显示,高达82.8%(53/64例)的患者为C群菌株感染,与其他群流脑比较,C群感染者病情重,病死率高.结论 C群脑膜炎奈瑟菌已成为目前安徽省流脑流行的主要菌株,C群感染者多见于青少年和成人.治疗以青霉素、第三代头孢菌素类抗菌药物为佳.     

PCR identification of the group A Neisseria meningitidis gene in cerebrospinal fluid

The aim of this study was to develop a PCR method for direct identification of Neisseria meningitidis serogroup A in cerebrospinal fluid. The assay makes use of unique sites within the gene cassette responsible for expression of the (alpha1 --> 6)-linked N-acetyl-D-mannosamine-1-phosphate serogroup A capsule. A total of 67 different N. meningitidis strains and 12 clinical samples of CSF, culture positive for N. meningitidis, were examined. All the strains and samples of N. meningitidis serogroup A were correctly identified by an amplified PCR product of 519 bp. The PCR method for identification is specific for the group A gene of N. meningitidis. The assay may contribute to reducing recurrent, devastating epidemics of meningococcal infection by providing a diagnostic tool for grouping in developing countries where problems with false negative cultures are common and vaccination against serogroup A meningococci may be required.     

Neisseria meningitidis serogroups A and W-135: carriage and immunity in Burkina Faso, 2003

OBJECTIVES: We sought to describe Neisseria meningitidis immunity and its association with pharyngeal carriage in Burkina Faso, where N. meningitidis serogroup W-135 and serogroup A disease are hyperendemic and most of the population received polysaccharide A/C vaccine during 2002. METHODS: We collected oropharyngeal swab samples from healthy residents of Bobo-Dioulasso (4-14 years old, n=238; 15-29 years old, n=250) monthly during February-June 2003; N. meningitidis isolates were analyzed using polymerase chain reaction and serogrouped using immune sera. Serum samples were collected at the first and last clinic visit and analyzed for anti-A, anti-C, anti-W-135, and anti-Y immunoglobulin G (IgG) concentrations and anti-A and anti-W-135 bactericidal titers. RESULTS: N. meningitidis was carried at least once by 18% of participants; this carriage included strains from serogroups W-135 (5%) and Y and X (both <1%) but not from serogroups A, B, or C. At baseline, the prevalence of putatively protective specific IgG concentrations (> or =2 microg/mL) and bactericidal titers (> or =8) was 85% and 54%, respectively, against serogroup A, and 6% and 22%, respectively, against serogroup W-135. Putatively protective anti-W-135 IgG concentrations and bactericidal titers were of short duration and were not associated with carriage. CONCLUSION: N. meningitidis serogroup W-135 strains did not induce immunity, despite their circulation. Carriage of serogroup A strains was rare despite the hyperendemic incidence of serogroup A meningitis during 2003 in Bobo-Dioulasso. A vaccine that includes serogroup W-135 antigen and eliminates serogroup A carriage is needed for sub-Saharan Africa.     

Immunoepidemiology of meningococcal disease in military recruits. I. A model for serogroup independency of epidemic potential as determined by serotyping.

One hundred twenty strains of Neisseria meningitidis were serotyped with use of cross-absorbed rabbit antisera in a bactericidal test. Fifty-eight epidemic strains of serogroup B, C, and Y that occurred simultaneously among military recruits at two basic training centers during a period of epidemic meningococcal disease were compared with 62 strains of serogroups A, B, C, and Y isolated worldwide. Antisera to the six original antigenic factors of the Gold serotyping schema were adequate for typing 94% of strains, including all of the epidemic strains. The array of serotyping factors in the epidemic strains differed from those in the nonepidemic strains. Epidemic strains were almost exclusively of two serotypes, with type CII predominant among strains of groups B and C. Concurrent strains of groups B and C were invariably of the same serotype. A model for the epidemic potential of meningococcal strains, which is based on their serotype and serogroup antigens, and a modification of the original Gold typing schema are presented.     

Bactericidal activity for Neisseria meningitidis in properdin-deficient sera

We investigated serum bactericidal reactions against Neisseria meningitidis (serogroups A, B, C, D, Y, W-135, 29E, X, and Z) in the sera of two healthy adults with properdin deficiency. Bactericidal reactions mediated via the classic complement pathway (unchelated system) were not impaired in properdin-deficient serum. The properdin-deficient sera supported alternative pathway-mediated killing (Mg++EGTA-chelated system) of some, but not all, of the strains investigated. Vaccination of the properdin-deficient individuals with serogroup A and C polysaccharide clearly increased the concentrations of antibody to meningococci. At least some of the antibodies induced by vaccination supported the bactericidal activity of properdin-deficient serum. Some antibodies to meningococci, probably of the IgM class, promoted alternative pathway-mediated bactericidal reactions in the absence of properdin. By contrast, presensitizing meningococci with IgG enhanced the alternative pathway-mediated reactions, but this was strictly a properdin-dependent effect.     

Antigenic diversity of Neisseria meningitidis isolated in Taiwan between 1995 and 2002

The geographic distribution of N. meningitidis is diverse. Information on the antigenic variation of N. meningitidis is important for the development of an outer membrane protein-based vaccine. As a first step towards vaccine development, serological typing was performed to determine the antigenic properties of 127 invasive N. meningitidis isolates collected in Taiwan between 1995 and 2002. With 31.5% non-serotypeable and 32.3% non-serosubtypeable, the 127 isolates fell into 51 phenotypes, with W135:NT:P1.5,2:L3,7,9, Y:14P1.5,2, and B:1:NST:L3,7,9 being the 3 most prevalent. Among the 37 serogroup B isolates, 15 serosubtypes were found, with P1.5,2 and P1.12,13 being the most prevalent. The high diversity of Por A among serogroup B isolates circulating in Taiwan poses a great challenge for the development of a PorA-based vaccine. Because 85% of the serogroup B isolates had the L3,7,9 immunotype, inclusion of L3,7,9 lipooligosaccharides in a PorA-based vaccine may be a promising approach. In addition, based on the phenotypic characterization, we suggest that both serogroup B and W135 isolates were endemic and that serogroup A, C, and Y isolates were imported, which may reflect increased international travel.     

Distribution of serogroups of Neisseria meningitidis and antigenic characterization of serogroup Y meningococci in Canada, January 1, 1999 to June 30, 2001.

The relative frequency of serogroups of Neisseria meningitidis associated with meningococcal disease in Canada during the period January 1, 1999 to June 30, 2001 was examined. Of the 552 strains of N meningitidis collected from clinical specimens of normally sterile sites, 191 (34.6%), 276 (50.0%), 61 (11.1%) and 23 (4.2%) were identified by serological and molecular methods as serogroups B, C, Y and W135, respectively. About half (50.8%) of the serogroup Y isolates were isolated in the province of Ontario. The two most common serotypes found were 2c and 14. Most of the serogroup Y strains isolated from patients in Ontario were serotype 2c, while serotype 14 was the most common serotype associated with disease in the province of Quebec. The two most common serosubtypes found among the serogroup Y meningococci were P1.5 and P1.2,5. Laboratory findings, based on antigenic analysis, did not suggest that these serogroup Y strains arise by capsule switching from serogroups B and C strains. This study documented a higher incidence of finding serogroup Y meningococci in clinical specimens from patients in Ontario compared to the rest of Canada, and parallels the increase in serogroup Y meningococcal disease reported in some parts of the United States.     

Microheterogeneity of serogroup A (subgroup III) neisseria meningitidis during an outbreak in northern ghana

During a meningitis outbreak in the eastern subdistrict of the Kassena-Nankana District of the Upper East Region of Ghana, we analysed cerebrospinal fluid from suspected meningitis cases for the most common causative organisms. In 50 of 92 samples analysed, serogroup A Neisseria meningitidis were detected. The ages of serogroup A N. meningitidis patients ranged from 4 months to 64 years. The case fatality ratio was 20%. Coma or stupor on presentation worsened the prognosis. All serogroup A N. meningitidis isolates recovered revealed the A: 4: P1.9, 20 phenotype characteristic for the subgroup III clonal grouping. No evidence for resistance to penicillin G, chloramphenicol, cefotaxime, ciprofloxacin, rifampicin or tetracycline was found. All strains were resistant to sulphadiazine. Restriction analysis patterns of opa, iga and ingA genes were characteristic for the majority of N. meningitidis serogroup A subgroup III bacteria isolated in Africa after the 1987 epidemic in Mecca. Differences in pulsed-field gel electrophoresis patterns of NheI and SpeI digested DNA revealed microheterogeneity among the Ghanaian isolates.