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1.
In 2000 the global outbreak that began in Saudi Arabia was caused by a W135:2a:P1.5,2 strain of Neisseria meningitidis belonging to the ET-37 complex and to ST-11. There was concern that introduction of this epidemic clone (EC) might lead to a wave of outbreaks in the African meningitis belt. The WHO therefore initiated studies of meningococcal carriage among pilgrims and their family contacts in Morocco, Oman and Sudan, 3 to 12 months after the Hajj 2000. In Morocco, 1186 persons were swabbed 3 times. Ninety-five meningococcal strains were isolated from 2.7% of the specimens. Pulsed-field gel electrophoresis showed that 32 (33.6%) were identical with the EC. In Sudan, 5 strains identical with the EC were obtained after sampling 285 persons. In Oman, among 18 meningococcal strains isolated from 399 subjects, 11 (61.1%) belonged to the EC. The important pharyngeal carriage of W135 (EC) and its role in the 2001-2002 outbreaks in Burkina Faso argues for the necessity of reinforcing surveillance, and adapting and planning responses in Africa and the Middle East using the most appropriate vaccine.  相似文献   

2.
NadA is a novel vaccine candidate recently identified in Neisseria meningitidis and involved in adhesion to host tissues. The nadA gene has been found in approximately 50% of the strains isolated from patients and in three of the four hypervirulent lineages of non-serogroup A strains. Here we investigated the presence of the nadA gene in 154 meningococcal strains isolated from healthy people (carrier strains). Only 25 (16.2%) of the 154 carrier isolates harbored the nadA gene. The commensal species Neisseria lactamica was also found not to have the nadA gene. Eighteen of the carrier strains belonged to the ET-5 and ET-37 hypervirulent clusters, indicating that only the 5.1% of the genuine carrier population actually harbored nadA (7 of 136 strains). Five of the seven strains harbored a novel allele of the nadA gene that was designated nadA4. The NadA4 protein was present on the bacterial surface as heat-stable high-molecular-weight oligomers. Antibodies against the recombinant NadA4 protein were bactericidal against homologous strains, whereas the activity against other NadA alleles was weak. In conclusion, the nadA gene segregates differently in the population of strains isolated from healthy individuals and in the population of strains isolated from patients. The presence of NadA can therefore be used as a tool to study the dynamics of meningococcal infections and understand why this bacterium, which is mostly a commensal, can become a severe pathogen.  相似文献   

3.
The aims of the study were to estimate the carrier state of Neisseria meningitidis in Swedish teenagers and its association with an outbreak at the World Scout Jamboree in 2015 as well as to compare sensitivity of throat versus nasopharyngeal swab for optimal detection of carriage. In total, 1 705 samples (cultures n = 32, throat swabs n = 715, nasopharyngeal swabs n = 958) from 1 020 Jamboree participants were collected and sent to the National Reference Laboratory for Neisseria meningitidis for culture and molecular analysis. The overall positivity for N. meningitidis was 8% (83/1 020), whereas 2% (n = 22) belonged to a known sero/genogroup while the majority (n = 61) were non‐groupable. Throat sample is clearly the sampling method of choice, in 56 individuals where both throat and nasopharynx samples were taken, N. meningitidis was detected in both throat and nasopharynx in eight individuals, in 46 individuals N. meningitidis was only detected in the throat and in two individuals only in the nasopharynx. Carriage studies are important to provide knowledge of the current epidemiology and association between carrier isolates and disease‐causing isolates in a given population. Therefore, planning for a carriage study in Sweden is in progress.  相似文献   

4.
Neisseria meningitidis W-135 accounted for nine (1.6%) of 562 cases of invasive meningococcal disease and 17 (3.9%) of 430 meningococcal isolates from healthy carriers. There was no mortality associated with the invasive nine isolates, which belonged to subtype P1.6 and geno-subtype P1.18-1. All invasive isolates and 15 of the 17 isolates from healthy carriers belonged to sequence type 22 by multilocus sequence typing, and showed a similarity of > 85% by pulsed-field gel electrophoresis following digestion with NheI. These results demonstrate that W-135 isolates in the Basque region of northern Spain have a high degree of similarity and are almost clonal.  相似文献   

5.
The relationship between carriage and the development of invasive meningococcal disease is not fully understood. We investigated the changes in meningococcal carriage in 892 military recruits in Finland during a nonepidemic period (July 2004 to January 2006) and characterized all of the oropharyngeal meningococcal isolates obtained (n = 215) by using phenotypic (serogrouping and serotyping) and genotypic (porA typing and multilocus sequence typing) methods. For comparison, 84 invasive meningococcal disease strains isolated in Finland between January 2004 and February 2006 were also analyzed. The rate of meningococcal carriage was significantly higher at the end of military service than on arrival (18% versus 2.2%; P < 0.001). Seventy-four percent of serogroupable carriage isolates belonged to serogroup B, and 24% belonged to serogroup Y. Most carriage isolates belonged to the carriage-associated ST-60 clonal complex. However, 21.5% belonged to the hyperinvasive ST-41/44 clonal complex. Isolates belonging to the ST-23 clonal complex were cultured more often from oropharyngeal samples taken during the acute phase of respiratory infection than from samples taken at health examinations at the beginning and end of military service (odds ratio [OR], 6.7; 95% confidence interval [95% CI], 2.7 to 16.4). The ST-32 clonal complex was associated with meningococcal disease (OR, 17.8; 95% CI, 3.8 to 81.2), while the ST-60 clonal complex was associated with carriage (OR, 10.7; 95% CI, 3.3 to 35.2). These findings point to the importance of meningococcal vaccination for military recruits and also to the need for an efficacious vaccine against serogroup B isolates.  相似文献   

6.
Fluorescent amplified-fragment length polymorphism (FAFLP), a genotyping technique with phylogenetic significance, was applied to 123 isolates of Neisseria meningitidis. Nine of these were from an outbreak in a British university; 9 were from a recent outbreak in Pontypridd, Glamorgan; 15 were from sporadic cases of meningococcal disease; 26 were from the National Collection of Type Cultures; 58 were carrier isolates from Ironville, Derbyshire; 1 was a disease isolate from Ironville; and five were representatives of invasive clones of N. meningitidis. FAFLP analysis results were compared with previously published multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) results. FAFLP was able to identify hypervirulent, hyperendemic lineages (invasive clones) of N. meningitidis as well as did MLST. PFGE did not discriminate between two strains from the outbreak that were classified as similar but distinct by FAFLP. The results suggest that high resolution of N. meningitidis for outbreak and other epidemiological analyses is more cost efficient by FAFLP than by sequencing procedures.  相似文献   

7.
The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Hungary has been increasing and is now close to 20% among invasive isolates of S. aureus . In order to understand the evolution of MRSA in Hungary, two collections of isolates were studied: 22 representatives of a collection of 238 MRSA isolates recovered between 1994 and 1998, and a collection of 299 MRSA isolates recovered between 2001 and 2004. The isolates were first characterised by pulsed-field gel electrophoresis (PFGE) and were distributed into 19 different PFGE patterns. Representatives of each pattern were further characterised by spa typing, multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCC mec ) typing. The Hungarian clone that was predominant in 1994–1998 (PFGE E, ST239-III) had almost disappeared in 2003–2004, being replaced by the Southern German clone (PFGE B, ST228-I) and the New York/Japan epidemic clone (PFGE A, ST5-II), which represented c.  85% of the 2001–2004 isolates. Thus, this study describes, for the first time, the co-dominance and extensive spread of the New York/Japan clone in a European country.  相似文献   

8.
Clinical isolates of Neisseria meningitidis from cases of meningococcal disease, collected between January 2000 and December 2004, were identified and typed at the French National Reference Centre. A representative subset of 546 isolates from among 2882 isolates was further genotyped by multilocus sequence typing to determine their genetic lineages (clonal complexes) and the degree of diversification among different clonal complexes. Representative isolates of the main clonal complexes were tested for their virulence in mice and for proapoptotic effects on human epithelial cells. High genetic diversity in some genetic lineages (ST-32 and ST-41/44) was correlated with heterogeneity in virulence in mice and proapoptotic effects on human epithelial cells. In contrast, the homogeneous genetic structure of isolates of the ST-11 clonal complex, regardless of their serogroup, correlated positively with a fatal outcome of the infection, increased virulence in mice and increased proapoptotic effects on human epithelial cells.  相似文献   

9.
The prevalence of clonal complex (CC) 398 methicillin-susceptible Staphylococcus aureus (MSSA) was unexpectedly high among bone and joint infections (BJIs) and nasal-colonizing isolates in France, with surprising geographical heterogeneity. With none of the major, most-known staphylococcal virulence genes, MSSA CC398 BJI was associated with lower biological inflammatory syndrome and lower treatment failure rates.  相似文献   

10.
It is essential in an outbreak investigation that strain characterization of Neisseria meningitidis is performed in a rapid and accurate manner. This study evaluated two new molecular typing methods, multiple‐locus variable number tandem repeat analysis (MLVA) and repetitive sequence‐based PCR (rep‐PCR) (DiversiLab; bioMérieux) and compared them with current recommended methodologies. This retrospective study included 36 invasive N. meningitidis serogroup C isolates collected in Sweden 2001 through 2009 and previously subjected to outbreak investigation. All strains were typed with highly variable‐MLVA (HV‐MLVA) and rep‐PCR. The isolates were further characterized by multilocus sequence typing (MLST) and sequencing of the fetA, fHbp, penA, porA and porB genes. The results showed that HV‐MLVA had the highest index of diversity (0.99) and rep‐PCR had the highest congruence (40%) with the currently recommended typing methods. The HV‐MLVA correlated best to the spatiotemporal connections and had the overall highest Adjusted Wallace coefficients, suggesting that HV‐MLVA can predict the results of the other typing methods in the study. We therefore suggest that after initial confirmation of species, serogroup and genosubtype, HV‐MLVA should be used as the most discriminatory method for first hand investigation of N. meningitidis serogroup C isolates.  相似文献   

11.

Purpose

Neisseria meningitidis is a leading cause of bacterial meningitis in young adults. University students, especially those living in dormitories, have been known to be at increased risk of meningococcal disease. We performed a longitudinal study to determine the carriage rates of N. meningitidis and the changes thereof.

Materials and Methods

We recruited Inha University freshmen who were, at that time, admitted to a student dormitory. A pharyngeal swab was taken from all participant who were also asked to complete a questionnaire. This was repeated four weeks later.

Results

A total of 136 students were enrolled at the first culture. After four weeks, 128 students were enrolled, including 106 re-participants. The overall carriage rates changed from 11.8% to 14.1%. In analysis of the 106 re-participants, "visiting to pubs" was associated with carriage of N. meningitis for both the first (p=0.047) and second cultures (p=0.026). Serogroup C was found to be the most frequent serogroup (5 isolates), while 3 isolates were found from serogroup B. The most prevalent PorA types were P1.22,14-6 (4 isolates) and P1.19,15 (3 isolates). The DNA sequences of PorA VR2 were changed in 2 students during prolonged carriage.

Conclusion

The meningococcal carriage rate among first year university students who resided in a dormitory did not significantly increase over 4-week interval between cultures, which is markedly different from those reported in Western studies. Close social contact appeared to be related with carriage. Our data also revealed diversity in PorA types, suggesting the possibility of rapid mutation of the PorA gene during the 4-week interval.  相似文献   

12.
This study aimed to characterise Neisseria meningitidis C:2b:P1.2,5 isolates from Poland, which have now become predominant among serogroup C isolates in this country. Overall, 44 isolates (25 invasive and 19 from contact carriers) were typed by whole-cell ELISA and pulsed-field gel electrophoresis. Additionally, the invasive isolates were analysed by multilocus sequence typing, which revealed that they all belonged to the ST-8 complex/cluster A4. The emergence of this clone in other countries has resulted in mass immunisation campaigns and has been associated with a higher level of decreased susceptibility to penicillin; however the present study detected only one isolate that was penicillin-non-susceptible.  相似文献   

13.
目的了解韶关市健康人群血清C群脑膜炎奈瑟菌杀菌力水平,以评价健康人群对C群脑膜炎奈瑟菌的保护水平。方法2009—2011年,每年随机抽取8个年龄组健康人群血清共计811份,采用血清杀菌力试验检测血清中杀菌力抗体水平。结果811份健康人群血清中C群脑膜炎奈瑟菌杀菌力抗体总阳性率为25.40%,总保护率为23.06%,GNT为l:5.13,95%置信区间1:4.57~1:5.89。结论韶关市健康人群对c群脑膜炎奈瑟菌的传染有易感性,年龄越低其对C群脑膜炎奈瑟菌的抵抗力越弱,应加大对A+C群流脑疫苗宣传力度,普及适龄儿童A+C群流脑疫苗的免疫接种。  相似文献   

14.
两株B群脑膜炎奈瑟氏菌脂寡糖减毒前后抗原性与毒性的检测孙银燕胡绪敬王君摘要脂寡糖(LOS)是B群Nm的一种主要外膜抗原,用SephacrylS-300HR或SephadexG-75凝胶层析方法从两株B群Nm(542852和3407)中提取获得了纯度较...  相似文献   

15.
目的 为保证生产四价流脑(A、C、W135、Y群)结合疫苗质量一致性和可控性,对分离自国内的W135、Y群脑膜炎球菌CMCC(B)29037株和CMCC(B)29028株进行免疫原性及遗传稳定性观察.方法 将W135/Y群脑膜炎球菌工作种子批菌种分别连续传代至30代,并收获3、5、10、15、20、25及30代次菌液,对各代次菌进行免疫原性、抗原性、生化反应、毒性、毒力测定,并将30代次菌发酵培养后提取荚膜多糖进行质量分析.结果 CMCC(B)29037株和CMCC(B)29028株工作种子批菌种诱导小鼠产生总IgG抗体分别为1∶1114和1∶2229,杀菌抗体水平与IgG抗体间差异无统计学意义;试管凝集效价均达到1∶320,生化检定两菌株均发酵葡萄糖、麦芽糖,不发酵果糖、蔗糖、甘露醇和乳糖;两菌株的LD50均>109,30代次内各代次菌的免疫原性、抗原性、生化反应和毒性均无差异.30代次菌液脑腔毒性测定显示均无病理改变,用第30代次菌生产的W135/Y群脑膜炎球菌荚膜多糖各项检定指标均合格.结论 分离自国内的CMCC(B)29037株和CMCC(B)29028株为脑膜炎球菌W135/Y群菌株,免疫原性、抗原性好,生化反应合格、安全性良好,连续传至30代次仍保持较好的安全性和免疫原性,30代次菌纯化的W135/Y群脑膜炎球菌荚膜多糖质量符合质控要求,可以用作四价流脑结合疫苗生产株.  相似文献   

16.
17.
In the Neisseria meningitidis strain MC58 (serogroup B; ET-5 complex) genome three putative islands of horizontally transferred DNA (IHTs) have been identified. IHT-A2 codes for eight hypothetical proteins and two disrupted open reading frames with similarity to a secretion protein (NMB0097) and an ABC transporter (NMB0098). The strains MC58 and 44/76 (shown here) are meningocin resistant/weakly sensitive. None of these strains are meningocin producers. However, NMB0097 and NMB0098 homologues with open reading frames are found in meningocin producers (N. meningitidis P241 (serogroup A; systemic isolate) and BT878 (serogroup B; carrier isolate), and also in strain FAM18 (serogroup C; ET-37 complex). Knocking out either of the two genes in the strain BT878 yielded mutants that did not secrete meningocin. A similarly disrupted tolC mutant in strain BT878 still released meningocin. Among systemic meningococcal isolates prior to and at the onset (mid-1973 to the end of 1974) of the epidemic peaking in 1975 in North Norway, 12 of 30 (40%) isolates of serogroup A were meningocin producers. However, the rate for serogroup B was 1 of 45 (2.2%). Serogroup B meningocin-resistant/weakly sensitive non-producers dominated in the region from mid-1975 and spread to the rest of the country from then on. No producers were found in selected pharyngeal isolates from healthy carriers collected in Svalbard in the early spring of 1975. Our results suggest that meningocinogeny has played a part in the change from serogroup A to serogroup B among isolates in North Norway during the first half of 1975.  相似文献   

18.
A library of Tn916-generated, tetracycline-resistant (Tc) mutants of the group B Neisseri meningitidis strain NMB was screened by using monoclonal antibodies (MAbs) that recognize structural differences in neisserial lipooligosaccharide (LOS). The LOS of parental strain NMB had a relative molecular mass of 4.5 kDa, reacted with MAbs 3F11 and 6B4 but not with MAb 4C4 or 6E4, and contained a lacto-N-neotetrose unit. Two phenotypically stable mutants, SS3 and R6, altered in LOS, were identified by colony immunoblots, electrophoresis, and Western immunoblots. The LOS of mutant SS3 was 3.4 kDa and reacted with MAbs 4C4 and 6E4 but not MAb 3E11 or 6B4. The LOS of mutant R6 was 3.1 to 3.2 kDa and reacted with MAb 6E4 but not MAb 3F11, 6B4, or 4C4. Thus, the LOSs of the R6 and SS3 mutants were predicted to contain different truncations of the core oligosaccharide. The LOS phenotype of each mutant was linked to Tc(r), as determined by transformation of the parent strain with DNA from the mutant. Southern hybridizations and single-specific-primer PCR revealed in each mutant a single truncated tn916 insertion which had lost genes required for mobilization. Tn916 mutagenesis was used to identify two distinct genetic sites in the meningococcal chromosome involved in biosynthesis of the oligosaccharide chain of LOS and to create genetically defined LOS mutants of N. meningitidis and Neisseria gonorrhoeae.  相似文献   

19.
The ability of 107 Neisseria isolates to compete for iron with human lactoferrin (LF) was examined. Each of 15 meningococci, 53% of 59 selected gonococci, and 24% of 33 commensal Neisseria could use LF-bound iron for growth. Isolates which could not obtain iron from LF were growth inhibited when sufficient LF was added to defined agar medium to bind available free iron. No difference was observed in the ability of colony type 1 and colony type 4 gonococci of the same strain to compete with LF for iron. LF was growth inhibitory for 50% of 22 disseminated disease isolates (DGI strains) and 51% of 35 local urogenital disease isolates (UGI strains). Only 14% of gonococcal isolates requiring arginine, hypoxanthine, and uracil for growth were able to compete with LF for iron, whereas 87% of all other gonococcal isolates could do so (P less than 0.005). Ability to obtain iron from LF does not appear to be required for survival of Neisseria on mucosal surfaces, nor essential for invasion of the bloodstream by gonococci. However, ability to utilize LF as a source of iron may contribute to differences in pathogenicity among certain gonococcal isolates.  相似文献   

20.
Accidental nasopharyngeal colonization of a laboratory worker by a human disease isolate of Neisseria meningitidis allowed us to examine the variation in expression of outer membrane components and the host humoral response over time. There were quantitative differences in class 1 outer membrane protein expression in nasopharyngeal isolates obtained at different times. Isolates also showed phase variation of all four class 5 outer membrane proteins produced by the colonizing strain. After colonization, we detected new host serum immunoglobulin G antibodies directed against class 1, class 5, and H.8 outer membrane proteins.  相似文献   

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