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Resistance to β-Lactams in Neisseria ssp Due to Chromosomally Encoded Penicillin-Binding Proteins. Antibiotics (Basel) 2016; 5:antibiotics5040035. [PMID: 27690121 PMCID: PMC5187516 DOI: 10.3390/antibiotics5040035] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 01/07/2023] Open
Abstract
Neisseria meningitidis and Neisseria gonorrhoeae are human pathogens that cause a variety of life-threatening systemic and local infections, such as meningitis or gonorrhoea. The treatment of such infection is becoming more difficult due to antibiotic resistance. The focus of this review is on the mechanism of reduced susceptibility to penicillin and other β-lactams due to the modification of chromosomally encoded penicillin-binding proteins (PBP), in particular PBP2 encoded by the penA gene. The variety of penA alleles and resulting variant PBP2 enzymes is described and the important amino acid substitutions are presented and discussed in a structural context.
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Bai X, Borrow R. Genetic shifts ofNeisseria meningitidisserogroup B antigens and the quest for a broadly cross-protective vaccine. Expert Rev Vaccines 2014; 9:1203-17. [DOI: 10.1586/erv.10.116] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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3
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Zarantonelli ML, Skoczynska A, Antignac A, El Ghachi M, Deghmane AE, Szatanik M, Mulet C, Werts C, Peduto L, d'Andon MF, Thouron F, Nato F, Lebourhis L, Philpott DJ, Girardin SE, Vives FL, Sansonetti P, Eberl G, Pedron T, Taha MK, Boneca IG. Penicillin resistance compromises Nod1-dependent proinflammatory activity and virulence fitness of neisseria meningitidis. Cell Host Microbe 2013; 13:735-45. [PMID: 23768497 DOI: 10.1016/j.chom.2013.04.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 03/05/2013] [Accepted: 04/30/2013] [Indexed: 12/12/2022]
Abstract
Neisseria meningitidis is a life-threatening human bacterial pathogen responsible for pneumonia, sepsis, and meningitis. Meningococcal strains with reduced susceptibility to penicillin G (Pen(I)) carry a mutated penicillin-binding protein (PBP2) resulting in a modified peptidoglycan structure. Despite their antibiotic resistance, Pen(I) strains have failed to expand clonally. We analyzed the biological consequences of PBP2 alteration among clinical meningococcal strains and found that peptidoglycan modifications of the Pen(I) strain resulted in diminished in vitro Nod1-dependent proinflammatory activity. In an influenza virus-meningococcal sequential mouse model mimicking human disease, wild-type meningococci induced a Nod1-dependent inflammatory response, colonizing the lungs and surviving in the blood. In contrast, isogenic Pen(I) strains were attenuated for such response and were out-competed by meningococci sensitive to penicillin G. Our results suggest that antibiotic resistance imposes a cost to the success of the pathogen and may potentially explain the lack of clonal expansion of Pen(I) strains.
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Draft Genome Sequence of a Neisseria meningitidis Serogroup C Isolate of Sequence Type 11 Linked to an Outbreak among Men Who Have Sex with Men. GENOME ANNOUNCEMENTS 2013; 1:1/5/e00795-13. [PMID: 24092789 PMCID: PMC3790093 DOI: 10.1128/genomea.00795-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Meningococcal disease occurs as sporadic cases in developed countries, with the occasional emergence of new clones of Neisseria meningitidis. Here, we report the genome sequence of N. meningitidis strain LNP27256, an isolate of sequence type 11 linked to a recent outbreak among men who have sex with men in Europe.
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Description of an unusual Neisseria meningitidis isolate containing and expressing Neisseria gonorrhoeae-Specific 16S rRNA gene sequences. J Clin Microbiol 2013; 51:3199-206. [PMID: 23863567 DOI: 10.1128/jcm.00309-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
An apparently rare Neisseria meningitidis isolate containing one copy of a Neisseria gonorrhoeae 16S rRNA gene is described herein. This isolate was identified as N. meningitidis by biochemical identification methods but generated a positive signal with Gen-Probe Aptima assays for the detection of Neisseria gonorrhoeae. Direct 16S rRNA gene sequencing of the purified isolate revealed mixed bases in signature regions that allow for discrimination between N. meningitidis and N. gonorrhoeae. The mixed bases were resolved by sequencing individually PCR-amplified single copies of the genomic 16S rRNA gene. A total of 121 discrete sequences were obtained; 92 (76%) were N. meningitidis sequences, and 29 (24%) were N. gonorrhoeae sequences. Based on the ratio of species-specific sequences, the N. meningitidis strain seems to have replaced one of its four intrinsic 16S rRNA genes with the gonococcal gene. Fluorescence in situ hybridization (FISH) probes specific for meningococcal and gonococcal rRNA were used to demonstrate the expression of the rRNA genes. Interestingly, the clinical isolate described here expresses both N. meningitidis and N. gonorrhoeae 16S rRNA genes, as shown by positive FISH signals with both probes. This explains why the probes for N. gonorrhoeae in the Gen-Probe Aptima assays cross-react with this N. meningitidis isolate. The N. meningitidis isolate described must have obtained N. gonorrhoeae-specific DNA through interspecies recombination.
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Hong E, Giorgini D, Deghmane AE, Taha MK. Functional impacts of the diversity of the meningococcal factor H binding protein. Vaccine 2012; 31:183-9. [DOI: 10.1016/j.vaccine.2012.10.072] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 08/29/2012] [Accepted: 10/20/2012] [Indexed: 11/27/2022]
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7
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Clonal analysis of Neisseria meningitidis serogroup B strains in South Africa, 2002 to 2006: emergence of new clone ST-4240/6688. J Clin Microbiol 2012; 50:3678-86. [PMID: 22972827 DOI: 10.1128/jcm.01079-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
From August 1999 through July 2002, hyperinvasive Neisseria meningitidis serogroup B (MenB) clonal complexes (CCs), namely, ST-32/ET-5 (CC32) and ST-41/44/lineage 3 (CC41/44), were predominant in the Western Cape Province of South Africa. This study analyzed MenB invasive isolates from a national laboratory-based surveillance system that were collected from January 2002 through December 2006. Isolates were characterized by pulsed-field gel electrophoresis (PFGE) (n = 302), and multilocus sequence typing (MLST) and PorA and FetA typing were performed on randomly selected isolates (34/302, 11%). In total, 2,400 cases were reported, with the highest numbers from Gauteng Province (1,307/2,400, 54%) and Western Cape Province (393/2,400, 16%); 67% (1,617/2,400) had viable isolates and 19% (307/1,617) were identified as serogroup B. MenB incidence remained stable over time (P = 0.77) (average incidence, 0.13/100,000 population [range, 0.10 to 0.16/100,000 population]). PFGE (302/307, 98%) divided isolates (206/302, 68%) into 13 clusters and 96 outliers. The largest cluster, B1, accounted for 25% of isolates (76/302) over the study period; its prevalence decreased from 43% (20/47) in 2002 to 13% (8/62) in 2006 (P < 0.001), and it was common in the Western Cape (58/76, 76%). Clusters B2 and B3 accounted for 10% (31/302) and 6% (19/302), respectively, and showed no significant change over time and were predominant in Gauteng. Randomly selected isolates from clusters B1, B2, and B3 belonged to CC32, CC41/44, and the new CC4240/6688, respectively. Overall, 15 PorA and 12 FetA types were identified. MenB isolates were mostly diverse with no single dominant clone; however, CC32 and CC41/44 accounted for 35% and the new CC4240/6688 was the third most prevalent clone.
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Garnier F, Courouble M, Denis F, Ploy MC. Emergence of 2 Neisseria meningitidis serogroup C clones in a French county. Diagn Microbiol Infect Dis 2011; 69:280-2. [PMID: 21353952 DOI: 10.1016/j.diagmicrobio.2010.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 09/14/2010] [Accepted: 09/29/2010] [Indexed: 11/27/2022]
Abstract
Between 2003 and 2007, we recovered 21 serogroup C Neisseria meningitidis isolates in the Haute-Vienne county of France. Multilocus sequence typing showed that 20 isolates belonged to the ST-11 clonal complex (8 to clone ET-15 and 12 to clone ET-37) and 1 to the ST-8 clonal complex.
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Affiliation(s)
- Fabien Garnier
- Laboratoire de Bactériologie-Virologie-Hygiène, Centre Hospitalier Universitaire de Limoges, 87042 Limoges Cedex, France.
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Skoczynska A, Ruckly C, Hong E, Taha MK. Molecular characterization of resistance to rifampicin in clinical isolates of Neisseria meningitidis. Clin Microbiol Infect 2009; 15:1178-81. [DOI: 10.1111/j.1469-0691.2009.02783.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Tribble GD, Lamont GJ, Progulske-Fox A, Lamont RJ. Conjugal transfer of chromosomal DNA contributes to genetic variation in the oral pathogen Porphyromonas gingivalis. J Bacteriol 2007; 189:6382-8. [PMID: 17573478 PMCID: PMC1951918 DOI: 10.1128/jb.00460-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porphyromonas gingivalis is a major oral pathogen that contributes to the development of periodontal disease. There is a significant degree of genetic variation among strains of P. gingivalis, and the population structure has been predicted to be panmictic, indicating that horizontal DNA transfer and recombination between strains are likely. The molecular events underlying this genetic exchange are not understood, although a putative type IV secretion system is present in the genome sequence of strain W83, implying that DNA conjugation may be responsible for genetic transfer in these bacteria. In this study, we provide in vitro evidence for the horizontal transfer of DNA using plasmid- and chromosome-based assays. In the plasmid assays, Bacteroides-derived shuttle vectors were tested for transfer from P. gingivalis strains into Escherichia coli. Of the eight strains tested, five were able to transfer DNA into E. coli by a mechanism most consistent with conjugation. Additionally, strains W83 and 33277 tested positive for the transfer of chromosomally integrated antibiotic resistance markers. Ten chimeras resulting from the chromosomal transfer assay were further analyzed by Southern hybridization and were shown to have exchanged DNA fragments of between 1.1 and 5.6 kb, but the overall strain identity remained intact. Chimeras showed phenotypic changes in the ability to accrete into biofilms, implying that DNA transfer events are sufficient to generate measurable changes in complex behaviors. This ability to transfer chromosomal DNA between strains may be an adaptation mechanism in the complex environment of the host oral cavity.
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Affiliation(s)
- Gena D Tribble
- Department of Oral Biology and Center for Molecular Microbiology, College of Dentistry, University of Florida, Gainesville 32610-0424, USA.
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Brehony C, Jolley KA, Maiden MCJ. Multilocus sequence typing for global surveillance of meningococcal disease. FEMS Microbiol Rev 2007; 31:15-26. [PMID: 17168997 DOI: 10.1111/j.1574-6976.2006.00056.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The global surveillance of bacterial pathogens is particularly important for bacteria with diverse and dynamic populations that cause periodic epidemics or pandemics. The isolate characterization methods employed for surveillance should: (1) generate unambiguous data; (2) be readily implemented in a variety of scenarios and be reproducible among laboratories; (3) be scalable and preferably available in a high throughput format; and (4) be cost effective. Multilocus sequence typing (MLST) was designed to meet these criteria and has been implemented effectively for a wide range of microorganisms. The 'Impact of meningococcal epidemiology and population biology on public health in Europe (EU-MenNet)' project had amongst its objectives: (1) to disseminate meningococcal MLST and sequence-based typing throughout Europe by establishing a centre for training and data generation, and (2) to produce a comprehensive Europe-wide picture of meningococcal disease epidemiology for the first time. Data produced from the project have shown the distribution of a relatively small number of STs, clonal complexes and PorA types that account for a large proportion of the disease-associated isolates in Europe. The project demonstrates how molecular typing can be combined with epidemiological data via the Internet for global disease surveillance.
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Affiliation(s)
- Carina Brehony
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, Oxford, UK
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12
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Abstract
Multilocus sequence typing (MLST) was proposed in 1998 as a portable, universal, and definitive method for characterizing bacteria, using the human pathogen Neisseria meningitidis as an example. In addition to providing a standardized approach to data collection, by examining the nucleotide sequences of multiple loci encoding housekeeping genes, or fragments of them, MLST data are made freely available over the Internet to ensure that a uniform nomenclature is readily available to all those interested in categorizing bacteria. At the time of writing, over thirty MLST schemes have been published and made available on the Internet, mostly for pathogenic bacteria, although there are schemes for pathogenic fungi and some nonpathogenic bacteria. MLST data have been employed in epidemiological investigations of various scales and in studies of the population biology, pathogenicity, and evolution of bacteria. The increasing speed and reduced cost of nucleotide sequence determination, together with improved web-based databases and analysis tools, present the prospect of increasingly wide application of MLST.
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Affiliation(s)
- Martin C J Maiden
- Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, Oxford, OX1 3SY, United Kingdom.
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13
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Jolley KA, Brehony C, Maiden MCJ. Molecular typing of meningococci: recommendations for target choice and nomenclature. FEMS Microbiol Rev 2006; 31:89-96. [PMID: 17168996 DOI: 10.1111/j.1574-6976.2006.00057.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The diversity and dynamics of Neisseria meningitidis populations generate a requirement for high resolution, comprehensive, and portable typing schemes for meningococcal disease surveillance. Molecular approaches, specifically DNA amplification and sequencing, are the methods of choice for various reasons, including: their generic nature and portability, comprehensive coverage, and ready implementation to culture negative clinical specimens. The following target genes are recommended: (1) the variable regions of the antigen-encoding genes porA and fetA and, if additional resolution is required, the porB gene for rapid investigation of disease outbreaks and investigating the distribution of antigenic variants; (2) the seven multilocus sequence typing loci-these data are essential for the most effective national, and international management of meningococcal disease, as well as being invaluable in studies of meningococcal population biology and evolution. These targets have been employed extensively in reference laboratories throughout the world and validated protocols have been published. It is further recommended that a modified nomenclature be adopted of the form: serogroup: PorA type: FetA type: sequence type (clonal complex), thus: B: P1.19,15: F5-1: ST-33 (cc32).
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Affiliation(s)
- Keith A Jolley
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, Oxford, UK
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FERREIRA E, DIAS R, CANIÇA M. Antimicrobial susceptibility, serotype and genotype distribution of meningococci in Portugal, 2001-2002. Epidemiol Infect 2006; 134:1203-7. [PMID: 16740192 PMCID: PMC2870526 DOI: 10.1017/s0950268806006492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2006] [Indexed: 11/06/2022] Open
Abstract
One hundred and eighteen Neisseria meningitidis isolates were recovered from patients with invasive meningococcal disease in Portugal, over one year. Our study was undertaken to evaluate antimicrobial susceptibility, serogroup, serotype and genotype of isolates. One quarter (24.6%) of the isolates showed moderate resistance to penicillin and 47.4% were resistant to sulphadiazine. The two most common serosubtypes were C:2b:P1.5,2 (31.3%) and B:4:P1.15 (3.4%). Half (53.6%) of the isolates with moderate resistance to penicillin were phenotype C:2b:P1.5,2 (n=14), C:2b:P1.2 (n=1) or C:2b:NST (n=1); Pulsed-field gel electrophoresis (PFGE) showed that all these isolates were genetically related. Multilocus sequence typing (MLST) analysis of representative clones from each PFGE pattern showed the predominance of the ST-8 complex/cluster A4 among N. meningitidis with moderate resistance to penicillin. This clonal complex has been principally found in Southern Europe. The apparent emergence and dissemination of the hypervirulent ST-8 complex/cluster A4 among serogroup C strains increases the need for a continued surveillance of antimicrobial susceptibility of meningococci and of genotypic markers in Portugal.
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Affiliation(s)
- E. FERREIRA
- Antibiotic Resistance Unit, Centre of Bacteriology, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
| | - R. DIAS
- Antibiotic Resistance Unit, Centre of Bacteriology, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
| | - M. CANIÇA
- Antibiotic Resistance Unit, Centre of Bacteriology, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
- Author for correspondence: Dr M. Caniça, Antibiotic Resistance Unit, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal. ()
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Smith I, Caugant DA, Høiby EA, Wentzel-Larsen T, Halstensen A. High case-fatality rates of meningococcal disease in Western Norway caused by serogroup C strains belonging to both sequence type (ST)-32 and ST-11 complexes, 1985-2002. Epidemiol Infect 2006; 134:1195-202. [PMID: 16650328 PMCID: PMC2870511 DOI: 10.1017/s0950268806006248] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2006] [Indexed: 11/05/2022] Open
Abstract
A total of 293 meningococcal disease (McD) patients from Western Norway hospitalized during 1985-2002 were examined for risk factors related to death. The case-fatality rate (CFR) increased from 4% during 1985-1993 to 17% during 1994-2002. We analysed the phenotypic and genotypic characteristics of the meningococcal patient isolates, with the aim of identifying whether highly virulent meningococcal strains contributed to the increased CFR. The Norwegian epidemic strain B:15:P1.7,16/ST-32 complex was overall the most common phenotype/genotype (n=75) and caused most deaths (n=9; CFR 12.0%). However, fatality was significantly associated with disease caused by serogroup C meningococcal strains; C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains, which had the highest CFRs of 21.1% and 18.2% respectively. Serogroup B strains of the ST-32 complex differing by serotype and/or serosubtype from the epidemic strain had a CFR of 5.1%, while the CFR of disease caused by other strains (all phenotypes and genotypes pooled) was 2.2%. The distribution of phenotypes/clonal complexes varied significantly between 1985-1993 and 1994-2002 (P<0.001); B:15/ST-32 complex strains decreased whereas both C:15:P1.7,16/ST-32 complex strains and strains with other phenotypes/clonal complexes increased. Our results indicate that C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains were highly virulent strains and contributed to the high CFR of McD in patients from Western Norway. To reduce fatality, rapid identification of such virulent strains is necessary. In addition, early and specific measures should include public information, vaccination of populations at risk of disease and carriage eradication, when clustering of patients occurs.
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Affiliation(s)
- I Smith
- Institute of Medicine, University of Bergen, Bergen, Norway.
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Zarantonelli ML, Antignac A, Lancellotti M, Guiyoule A, Alonso JM, Taha MK. Immunogenicity of meningococcal PBP2 during natural infection and protective activity of anti-PBP2 antibodies against meningococcal bacteraemia in mice. J Antimicrob Chemother 2006; 57:924-30. [PMID: 16513914 DOI: 10.1093/jac/dkl066] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE To evaluate the immunogenicity of the meningococcal penicillin-binding protein 2 (PBP2) and its potential as a vaccine candidate. METHODS The immunogenicity of meningococcal PBP2 was investigated using acute and convalescent sera from patients who recovered from meningococcal disease. Sera were tested against purified recombinant PBP2s corresponding to meningococcal isolates of different genetic lineages, of different serogroups and with various susceptibility levels to penicillin G. Mice were vaccinated with recombinant PBP2 and challenged with Neisseria meningitidis. A purified anti-PBP2 rabbit IgG was also used for passive protection experiments in mice. RESULTS Convalescent patients' sera recognized PBP2s from different strains, showing that this protein is immunogenic in meningococcal disease. Vaccination with purified recombinant PBP2 and purified anti-PBP2 rabbit IgG antibody conferred protection against experimental meningococcaemia in mice. CONCLUSION These data argue for considering meningococcal PBP2 as a vaccine candidate.
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Affiliation(s)
- Maria Leticia Zarantonelli
- Neisseria Unit, National Reference Center for Meningococci, Department of Molecular Medicine, Institut Pasteur, 25-28 rue du Dr Roux, 75724 Paris Cedex 15, France.
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17
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Baldo L, Bordenstein S, Wernegreen JJ, Werren JH. Widespread recombination throughout Wolbachia genomes. Mol Biol Evol 2005; 23:437-49. [PMID: 16267140 DOI: 10.1093/molbev/msj049] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Evidence is growing that homologous recombination is a powerful source of genetic variability among closely related free-living bacteria. Here we investigate the extent of recombination among housekeeping genes of the endosymbiotic bacteria Wolbachia. Four housekeeping genes, gltA, dnaA, ftsZ, and groEL, were sequenced from a sample of 22 strains belonging to supergroups A and B. Sequence alignments were searched for recombination within and between genes using phylogenetic inference, analysis of genetic variation, and four recombination detection programs (MaxChi, Chimera, RDP, and Geneconv). Independent analyses indicate no or weak intragenic recombination in ftsZ, dnaA, and groEL. Intragenic recombination affects gltA, with a clear evidence of horizontal DNA transfers within and between divergent Wolbachia supergroups. Intergenic recombination was detected between all pairs of genes, suggesting either a horizontal exchange of a genome portion encompassing several genes or multiple recombination events involving smaller tracts along the genome. Overall, the observed pattern is compatible with pervasive recombination. Such results, combined with previous evidence of recombination in a surface protein, phage, and IS elements, support an unexpected chimeric origin of Wolbachia strains, with important implications for Wolbachia phylogeny and adaptation of these obligate intracellular bacteria in arthropods.
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Affiliation(s)
- Laura Baldo
- Department of Biology, University of California, Riverside, USA.
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Abstract
Neisseria meningitidis can cause asymptomatic carriage, followed by acquired immunity, or septicaemia, meningitis, septic arthritis or pericarditis. Vaccination induces protective bactericidal antibodies to invasive diseases. Meningococcal capsular polysaccharides are immunoprotective antigens from which vaccines are produced against serogroups A, C, Y and W135, including conjugate vaccines against serogroup C. There is no available vaccine against serogroup B, but outermembrane protein-based vaccines against this serogroup are currently being evaluated. Polysaccharide meningococcal vaccines are effective, but their strictly serogroup-specific efficacy raises concerns about the possible selection of escape variants. Therefore, meningococcal polysaccharide vaccines, either plain or conjugated, are indicated against the clonal expansion of strains whose serogroup has been properly identified and corresponds to the vaccine valence.
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Affiliation(s)
- Jean-Michel Alonso
- Unité des Neisseria, Centre National de Référence des Méningocoques, Departement de Médecine Moléculaire, Institut Pasteur, Paris, France.
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Dyet KH, Martin DR. Sequence variation in the porB gene from B:P1.4 meningococci causing New Zealand's epidemic. J Clin Microbiol 2005; 43:838-42. [PMID: 15695689 PMCID: PMC548081 DOI: 10.1128/jcm.43.2.838-842.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since mid-1991, New Zealand has experienced an epidemic of meningococcal disease. The epidemic has been caused by serogroup B meningococci expressing PorA type P1.7-2,4, belonging to the ST-41/ST-44 complex, lineage III. Most B:P1.7-2,4 meningococci express type 4 PorB (87.0%), although case isolates with porB other than type 4 have been identified throughout the duration of the epidemic. To assess the genetic relatedness of case isolates with an alternative porB gene, multilocus restriction typing validated against multilocus sequence typing was used. This determined that B:P1.7-2,4 meningococci with a porB gene that was other than type 4 had the same clonal origin. It was concluded that strains with alternative porB genes had diverged from the original type 4 porB. Variation in porB was also shown to be associated with the uptake of DNA encoding one or two of the PorB variable regions leading to mosaic porB. Point mutation rather than horizontal transfer and recombination was implicated as the mechanism of sequence variation in some strains. This work will serve as a reference point to determine if the administration of a strain-specific vaccine increases the level of porB divergence and variation already observed in New Zealand case isolates. It also complements the study undertaken of PorA stability which showed that variation in P1.7-2,4 PorA was almost exclusively due to deletions in the P1.4 epitope of the epidemic strain.
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Affiliation(s)
- Kristin H Dyet
- Communicable Disease Group, Institute of Environmental Science and Research, Porirua, New Zealand
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Njanpop-Lafourcade BM, Parent du Châtelet I, Sanou O, Alonso JM, Taha MK. The establishment of Neisseria meningitidis serogroup W135 of the clonal complex ET-37/ST-11 as an epidemic clone and the persistence of serogroup A isolates in Burkina Faso. Microbes Infect 2005; 7:645-9. [PMID: 15823512 DOI: 10.1016/j.micinf.2005.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Revised: 12/15/2004] [Accepted: 01/04/2005] [Indexed: 10/25/2022]
Abstract
We analyzed 48 invasive isolates of Neisseria meningitidis that were isolated from meningitis cases in Burkina Faso (April 2002 to April 2003). Thirty-nine of these isolates had the phenotype (serogroup:serotype:serosubtype) W135:2a:P1.5,2, eight isolates were A:4:P1.9 and one isolate was nongroupable:nonserotypable:nonserosubtypable. Genotyping of meningococcal isolates showed that W135 isolates belonged to the sequence type (ST)-11. The nongroupable isolate was of genogroup W135 and belonged to ST-192. Isolates of serogroup A belonged to ST-2859 (a member of the subgroup III/ST-5 clonal complex). W135 (ST-11) isolates involved in meningitis outbreaks in Burkina Faso differed from those involved in the Hajj-2000 associated outbreak by their pulsed-field gel electrophoresis profile. These data confirm the changing epidemiology of meningococcal infection in Burkina Faso with the establishment and expansion of serogroup W135 N. meningitidis strains of the ET-37/ST-11 clonal complex, as well as the emergence of a new clone within the subgroup III/ST-5 clonal complex.
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Taha MK, Alonso JM, Cafferkey M, Caugant DA, Clarke SC, Diggle MA, Fox A, Frosch M, Gray SJ, Guiver M, Heuberger S, Kalmusova J, Kesanopoulos K, Klem AM, Kriz P, Marsh J, Mölling P, Murphy K, Olcén P, Sanou O, Tzanakaki G, Vogel U. Interlaboratory comparison of PCR-based identification and genogrouping of Neisseria meningitidis. J Clin Microbiol 2005; 43:144-9. [PMID: 15634963 PMCID: PMC540131 DOI: 10.1128/jcm.43.1.144-149.2005] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Twenty clinical samples (18 cerebrospinal fluid samples and 2 articular fluid samples) were sent to 11 meningococcus reference centers located in 11 different countries. Ten of these laboratories are participating in the EU-MenNet program (a European Union-funded program) and are members of the European Monitoring Group on Meningococci. The remaining laboratory was located in Burkina Faso. Neisseria meningitidis was sought by detecting several meningococcus-specific genes (crgA, ctrA, 16S rRNA, and porA). The PCR-based nonculture method for the detection of N. meningitidis gave similar results between participants with a mean sensitivity and specificity of 89.7 and 92.7%, respectively. Most of the laboratories also performed genogrouping assays (siaD and mynB/sacC). The performance of genogrouping was more variable between laboratories, with a mean sensitivity of 72.7%. Genogroup B gave the best correlation between participants, as all laboratories routinely perform this PCR. The results for genogroups A and W135 were less similar between the eight participating laboratories that performed these PCRs.
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Affiliation(s)
- Muhamed-Kheir Taha
- Neisseria Unit and the French National Reference Center for Meningococci, Institut Pasteur, Paris, France.
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Jordan P, Snyder LAS, Saunders NJ. Diversity in coding tandem repeats in related Neisseria spp. BMC Microbiol 2003; 3:23. [PMID: 14611665 PMCID: PMC305346 DOI: 10.1186/1471-2180-3-23] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Accepted: 11/12/2003] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Tandem repeats contained within coding regions can mediate phase variation when the repeated units change the reading frame of the coding sequence in a copy number dependent manner. Coding tandem repeats are those which do not alter the reading frame with copy number, and the changes in copy number of these repeats may then potentially alter the function or antigenicity of the protein encoded. Three complete neisserial genomes were analyzed and compared to identify coding tandem repeats where the number of copies of the repeat will have some structural consequence for the protein. This is the first study to address coding tandem repeats that may affect protein structures using comparative genomics, combined with a population survey to investigate which show interstrain variability. RESULTS A total of 28 genes were identified. Of these, 22 contain coding tandem repeats that vary in copy number between the three sequenced strains, three strain specific genes were included for investigation on the basis of having >90% identity between repeated units, and three genes with repeated elements of >250 bp were included although no length variations were seen in the genomes. Amplification, and sequencing of repeats showing altered copy number, of these 28 coding tandem repeat containing regions, from a set of largely unrelated strains, revealed further repeat length variation in several cases. CONCLUSION Eighteen genes were identified which have variation in repeat copy number between strains of the same species, twelve of which show greater diversity in repeat copy number than is present in the sequenced genomes. In some cases, this may reflect a mechanism for the generation of antigenic variation, as previously described in other species. However, some of the genes identified encode proteins with cytoplasmic functions, including sugar metabolism, DNA repair, and protein production, in which repeat length variation may have other functions. Coding tandem repeats appear to represent a largely unexplored mechanism of generating diversity in the Neisseria spp.
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Affiliation(s)
- Philip Jordan
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford. OX1 3RE, UK
| | - Lori AS Snyder
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford. OX1 3RE, UK
| | - Nigel J Saunders
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford. OX1 3RE, UK
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Jensen ES, Schønheyder HC, Lind I, Berthelsen L, Nørgård B, Sørensen HT. Neisseria meningitidis phenotypic markers and septicaemia, disease progress and case-fatality rate of meningococcal disease: a 20-year population-based historical follow-up study in a Danish county. J Med Microbiol 2003; 52:173-179. [PMID: 12543925 DOI: 10.1099/jmm.0.04817-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The incidence rate (IR) and case-fatality rate (CFR) of meningococcal disease increased during the late 1980s and early 1990s in North Jutland County, Denmark. We examined the hypothesis that phenotypic markers of Neisseria meningitidis are predictors of septicaemia with or without meningitis, rapid disease progress and fatal outcome of meningococcal disease and we studied whether changes in IR and CFR over time might be related to emergence or spread of certain phenotypes. This follow-up study was based on a complete registration of 413 cases of meningococcal disease in North Jutland County during 1980-99. Phenotypic markers included serogroup, serotype and serosubtype. A complete phenotype was available for 315 cases (76 %); 100 (32 %) strains were phenotype B : 15 : P1.7,16 and 31 (10 %) were C : 2a : P1.2,5. Septicaemia without meningitis was less common in cases with B : 15 : P1.7,16 and C : 2a : P1.2,5 strains. No association was found between phenotype and rapid disease progress. The overall CFR was 12 %. An increased CFR was associated with phenotypes B : 15 : P1.7,16 [odds ratio (OR) 2.8, 95 % confidence interval (CI) 1.2-18.5] and C : 2a : P1.2,5 (OR 5.2, 95 % CI 1.6-16.4) when compared with other phenotypes. The prevalence of B : 15 : P1.7,16 strains increased gradually during the study period and the CFR increased from 8 % during 1980-89 to 19 % during 1990-99, although the CFR for other phenotypes also increased. The CFR for C : 2a : P1.2,5 remained high ( approximately 20 %), but the contribution of this phenotype to the overall CFR decreased during the study period. In conclusion, phenotypes B : 15 : P1.7,16 and C : 2a : P1.2,5 were predictors of an increased CFR. The high prevalence of phenotype B : 15 : P1.7,16 contributed to increased overall IR and CFR during 1990-99.
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Affiliation(s)
- Elise Snitker Jensen
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
| | - Henrik C Schønheyder
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
| | - Inga Lind
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
| | - Lene Berthelsen
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
| | - Bente Nørgård
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
| | - Henrik Toft Sørensen
- Department of Clinical Epidemiology, Aalborg and Aarhus University Hospital, Stengade 10, 2nd floor, DK-9000 Aalborg, Denmark 2Department of Clinical Microbiology, Aalborg Hospital, DK-9000 Aalborg, Denmark 3The Neisseria Unit, Statens Serum Institut, DK-2300 Copenhagen, Denmark
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24
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Abstract
Immediate management of meningococcal infections is a medical emergency that requires rapid identification and typing of bacterial strains. Isolation of Neisseria meningitidis is hindered by early antibiotic treatment. Molecular (nonculture) methods of diagnosis and characterization of N. meningitidis permit to overcome this failure. This bacterium is highly variable due to frequent horizontal DNA exchange between strains. Molecular approaches of typing allow a reliable tracking of meningococcal strains and a powerful epidemiological analysis.
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Affiliation(s)
- Muhamed-Kheir Taha
- Unité des Neisseria and Centre National de Reference des Méningocoque Institut Pasteur, 28 rue du Dr Roux, 75724 Paris, France.
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25
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Abstract
The evolution of antibiotic resistance provides a well-documented, rapid, and recent example of a selection driven process that has occurred in many bacterial species. An exhaustive collection of Moraxella catarrhalis that spans a transition to chromosomally encoded penicillin resistance was used to analyze genetic changes accompanying the transition. The population was characterized by high haplotypic diversity with 148 distinct haplotypes among 372 isolates tested at three genomic regions. The power of a temporally stratified sample from a single population was highlighted by the finding of high genetic diversity throughout the transition to resistance, population numbers that remained high over time, and no evidence of departures from neutrality in the allele frequency spectra throughout the transition. The direct temporal analysis documented the persistence, antibiotic status, and haplotypic identity of strains undergoing apparent clonal expansions. Several haplotypes that were beta-lactamase nonproducers in early samples converted to producers in later years. Maintenance of genetic diversity and haplotype conversions from sensitive to resistant supported the hypothesis that penicillin resistance determinants spread to a diverse array of strains via horizontal exchange. Genetic differentiation between sample years, estimated by F(ST), was increasing at a rate that could cause complete haplotype turnover in less than 150 years. Widespread linkage disequilibrium among sites within one locus (copB) suggested recent mutation followed by clonal expansion. Nonrandom associations between haplotypes and resistance phenotypes provided further evidence of clonal expansion for some haplotypes. Nevertheless, the population structure was far from clonal as evidenced by a relatively low frequency of disequilibria both within sites at a second locus (M46) as well as between loci. The haplotype-antibiotic resistance association that was accompanied by gradual haplotype turnover is consistent with a hypothesis of genetic drift at marker loci with directional selection at the resistance locus.
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Affiliation(s)
- E S Walker
- James H. Quillen Veterans Affairs Medical Center, Mountain Home, Tennessee 37684, USA.
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26
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Chen I, Gotschlich EC. ComE, a competence protein from Neisseria gonorrhoeae with DNA-binding activity. J Bacteriol 2001; 183:3160-8. [PMID: 11325945 PMCID: PMC95217 DOI: 10.1128/jb.183.10.3160-3168.2001] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae is naturally able to take up exogenous DNA and undergo genetic transformation. This ability correlates with the presence of functional type IV pili, and uptake of DNA is dependent on the presence of a specific 10-bp sequence. Among the known competence factors in N. gonorrhoeae, none has been shown to interact with the incoming DNA. Here we describe ComE, a DNA-binding protein involved in neisserial competence. The gene comE was identified through similarity searches in the gonococcal genome sequence, using as the query ComEA, the DNA receptor in competent Bacillus subtilis. The gene comE is present in four identical copies in the genomes of both N. gonorrhoeae and Neisseria meningitidis, located downstream of each of the rRNA operons. Single-copy deletion of comE in N. gonorrhoeae did not have a measurable effect on competence, whereas serial deletions led to gradual decrease in transformation frequencies, reaching a 4 x 10(4)-fold reduction when all copies were deleted. Transformation deficiency correlated with impaired ability to take up exogenous DNA; however, the mutants presented normal piliation and twitching motility phenotype. The product of comE has 99 amino acids, with a predicted signal peptide; by immunodetection, a 8-kDa protein corresponding to processed ComE was observed in different strains of N. gonorrhoeae and N. meningitidis. Recombinant His-tagged ComE showed DNA binding activity, without any detectable sequence specificity. Thus, we identified a novel gonococcal DNA-binding competence factor which is necessary for DNA uptake and does not affect pilus biogenesis or function.
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Affiliation(s)
- I Chen
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York 10021.
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27
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Ashton FE, Caugant DA. The panmictic nature ofNeisseria meningitidisserogroup B during a period of endemic disease in Canada. Can J Microbiol 2001. [DOI: 10.1139/w01-008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three hundred and one (301) strains of Neisseria meningitidis serogroup B, isolated from patients with meningococcal disease during the years 19941996, were subjected to multilocus enzyme electrophoresis, serotyping, and serosubtyping. Based on the analyses of 14 enzyme loci, 177 electrophoretic types (ETs) were identified. Of these, 136 were represented by single isolates and 41 were represented by multiple isolates (range 231). The mean genetic diversity for isolates was 0.444 and for ETs was 0.440. The index of association (IA) between loci was 0.530 ± 0.08 for isolates and 0.256 ± 0.10 for ETs. Cluster analysis revealed the presence of 39 lineages each represented by a single ET or clusters of ETs. The most common serotypes were 4, 15, and 14 and accounted for 84 (28.0%), 53 (17.6%), and 32 (10.6%) of the isolates, respectively, and were dispersed amongst 46 ETs (1122), 35 ETs (3165), and 26 ETs (1876), respectively. The 109 (36.6%) nontypable (NT) isolates were amongst 74 ETs (6177). The mean genetic diversity for serotypes 4, 15, and 14 and NT isolates was 0.368, 0.371, 0.343, and 0.442, respectively, and for ETs was 0.363, 0.354, 0.397, and 0.440, respectively. Combinations of serotypes and serosubtypes (number of isolates) that occurred most frequently were 4:P1.14 (17), 14:P1.16 (16), NT:P1.16 (16), 15:P1.16 (13), and NT:P1.13 (13). The majority of group B disease in Canada during 19941996 was caused by meningococci of considerable genetic diversity, and reflects a situation of endemic disease. However, the results also indicate that organisms belonging to the ET-5 complex, which has been responsible for outbreaks of group B disease globally for several decades, have been introduced into the country.Key words: meningococcal, genotypes, serotypes, serosubtypes, Neisseria meningitidis.
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28
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Tzanakaki G, Urwin R, Musilek M, Kriz P, Kremastinou J, Pangalis A, Blackwell CC, Maiden MC. Phenotypic and genotypic approaches to characterization of isolates of Neisseria meningitidis from patients and their close family contacts. J Clin Microbiol 2001; 39:1235-40. [PMID: 11283034 PMCID: PMC87917 DOI: 10.1128/jcm.39.4.1235-1240.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2000] [Accepted: 01/12/2001] [Indexed: 11/20/2022] Open
Abstract
Characterization of isolates of Neisseria meningitidis obtained from patients with meningococcal disease or from pharyngeal swabs of asymptomatic carriers can be achieved by several approaches which provide different levels of discrimination. A total of 45 gram negative, oxidase-positive diplococcus strains isolated from 15 individuals with meningococcal disease and 30 of their family contacts were examined by three approaches: serological typing, multilocus enzyme electrophoresis (MLEE), and multilocus sequence typing (MLST). For 10 of the 15 patient and contact groups, all of the isolates were confirmed as meningococci, and the bacteria obtained from the patients and contacts, including their mother or principal caregiver in the case of children, were indistinguishable by all three methods. In the remaining five groups the isolates from the patients were distinct from those recovered from the contacts, and in three examples, in two separate groups, the contacts were shown by MLST to be carrying strains of Neisseria lactamica. The data obtained from the three techniques were consistent, although complete serological typing was possible for only a minority of isolates. Both MLEE and MLST established the genetic relationships of the isolates and identified members of known hypervirulent lineages, but MLST was faster than MLEE and had the additional advantages that it could be performed on noninfective material distributed by mail and that the results from different laboratories could be compared via the internet (http://mlst.zoo.ox.ac.uk).
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Affiliation(s)
- G Tzanakaki
- National Meningococcal Reference Laboratory, National School of Public Health, Athens, Greece
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29
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Toropainen M, Saarinen L, van der Ley P, Kuipers B, Käyhty H. Murine monoclonal antibodies to PorA of Neisseria meningitidis show reduced protective activity in vivo against B:15:P1.7,16 subtype variants in an infant rat infection model. Microb Pathog 2001; 30:139-48. [PMID: 11273739 DOI: 10.1006/mpat.2000.0419] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The major outer membrane protein PorA of Neisseria meningitidis is the target for bactericidal serosubtyping antibodies and is currently considered as a potential vaccine candidate against group B meningococcal disease. Although the minor antigenic variability of the PorA has been increasingly recognized and described, its implication for vaccine design remains unclear. In this study, the protective activity of murine monoclonal PorA specific antibodies against four isogenic meningococcal P1.7,16 target strains, the prototype P1.7,16a and three loop 4 point mutation variants (designated P1.7,16b to d) constructed from reference strain H44/76 (B:15:P1.7,16a), was evaluated in the infant rat infection model. All monoclonal antibodies had been obtained by immunization of mice with outer membrane protein preparations from meningococcal serosubtype P1.7,16 reference strain H44/76. A challenge dose of 10(5)cfu/pup was given i.p. 1-2 h after the i.p. injection of 1:100 diluted antibodies, and the development of bacteremia was assessed by culturing blood samples taken 6 h after challenge. MN14C11.6, a reference monoclonal antibody for serosubtype P1.7 epitope located in predicted loop 1 (VR1) identical in all the variants, was equally protective against all loop 4 variants. The three P1.16 specific monoclonal antibodies tested (MN5C11G, MN12H2 and 62D12-8) all completely protected animals against the prototype P1.7,16a, variably against the P1.7,16b and P1.7,16c, but not against the P1.7,16d variant. Our findings therefore suggest that certain subtype variants may escape protection in vivo conferred by PorA specific antibodies.
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Affiliation(s)
- M Toropainen
- National Public Health Institute, Helsinki, Finland.
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30
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31
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Bart A, Dankert J, van der Ende A. Representational difference analysis of Neisseria meningitidis identifies sequences that are specific for the hyper-virulent lineage III clone. FEMS Microbiol Lett 2000; 188:111-4. [PMID: 10913691 DOI: 10.1111/j.1574-6968.2000.tb09179.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Neisseria meningitidis may cause meningitis and septicemia. Since the early 1980s, an increased incidence of meningococcal disease has been caused by the lineage III clone in many countries in Europe and in New Zealand. We hypothesized that lineage III meningococci have specific DNA sequences, providing an opportunity to facilitate epidemiological studies by detecting lineage III isolates rapidly. Applying representational difference analysis on one lineage III tester strain and two non-lineage III driver strains, we identified three lineage III-specific sequences, probably part of a single locus encoding a restriction modification system. A PCR based on one of these sequences identified lineage III meningococcal isolates with a sensitivity of 100% and a specificity of 93%, which is superior to the serological identification of lineage III isolates.
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Affiliation(s)
- A Bart
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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32
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Lafontaine ER, Cope LD, Aebi C, Latimer JL, McCracken GH, Hansen EJ. The UspA1 protein and a second type of UspA2 protein mediate adherence of Moraxella catarrhalis to human epithelial cells in vitro. J Bacteriol 2000; 182:1364-73. [PMID: 10671460 PMCID: PMC94425 DOI: 10.1128/jb.182.5.1364-1373.2000] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The UspA1 and UspA2 proteins of Moraxella catarrhalis are structurally related, are exposed on the bacterial cell surface, and migrate as very high-molecular-weight complexes in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Previous analysis of uspA1 and uspA2 mutants of M. catarrhalis strain 035E indicated that UspA1 was involved in adherence of this organism to Chang conjunctival epithelial cells in vitro and that expression of UspA2 was essential for resistance of this strain to killing by normal human serum (C. Aebi, E. R. Lafontaine, L. D. Cope, J. L. Latimer, S. R. Lumbley, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 66:3113-3119, 1998). In the present study, isogenic uspA1, uspA2, and uspA1 uspA2 mutations were constructed in three additional M. catarrhalis strains: 012E, TTA37, and 046E. The uspA1 mutant of strain 012E had a decreased ability to attach to Chang cells. However, inactivation of the uspA1 gene in both strain TTA37 and strain 046E did not cause a significant decrease in attachment ability. Inactivation of the uspA2 gene of strain TTA37 did result in a loss of attachment ability. Nucleotide sequence analysis revealed that the predicted protein encoded by the uspA2 genes of both strains TTA37 and 046E had a N-terminal half that resembled the N-terminal half of UspA1 proteins, whereas the C-terminal half of this protein was nearly identical to those of previously characterized UspA2 proteins. The gene encoding this "hybrid" protein was designated uspA2H. PCR-based analysis revealed that approximately 20% of M. catarrhalis strains apparently possess a uspA2H gene instead of a uspA2 gene. The M. catarrhalis uspA1, uspA2, and uspA2H genes were cloned and expressed in Haemophilus influenzae cells, which were used to prove that both the UspA1 and UspA2H proteins can function as adhesins in vitro.
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Affiliation(s)
- E R Lafontaine
- Departments of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9048, USA
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Menéndez T, Pérez M, Alvarez A. Antigenic and genetic characterization of a putative hybrid transferrin-binding protein B fromNeisseria meningitidis. Can J Microbiol 1999. [DOI: 10.1139/w99-100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transferrin-binding protein Bs (TbpBs) from the bacterium Neisseria meningitidis have been divided into two families according to genetic and antigenic features. TbpB from meningococcal strain B385 showed a molecular mass similar to that exhibited by TbpBs belonging to the high molecular mass family of TbpBs. TbpB was recognized by immunoassay using a specific serum directed against the TbpB of the reference strain for this family (strain M982). It was also recognized by a serum elicited against the TbpB of the reference strain for the low molecular mass family (strain B16B6). The tbpB gene from strain B385 was cloned and sequenced. The highest degree of sequence homology was found to be with the TbpBs belonging to the high molecular mass family, although a region of 14 amino acids that is only present in the TbpB from strain B16B6 was also found. This report illustrates a TbpB that shows hybrid antigenic and genetic behaviour.Key words: Neisseria meningitidis, transferrin-binding proteins, TbpB families.
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Bygraves JA, Urwin R, Fox AJ, Gray SJ, Russell JE, Feavers IM, Maiden MC. Population genetic and evolutionary approaches to analysis of Neisseria meningitidis isolates belonging to the ET-5 complex. J Bacteriol 1999; 181:5551-6. [PMID: 10482493 PMCID: PMC94072 DOI: 10.1128/jb.181.18.5551-5556.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/1999] [Accepted: 07/08/1999] [Indexed: 01/31/2023] Open
Abstract
Periodically, new disease-associated variants of the human pathogen Neisseria meningitidis arise. These meningococci diversify during spread, and related isolates recovered from different parts of the world have different genetic and antigenic characteristics. An example is the ET-5 complex, members of which were isolated globally from the mid-1970s onwards. Isolates from a hyperendemic outbreak of meningococcal disease in Worcester, England, during the late 1980s were characterized by multilocus sequence typing and sequence determination of antigen genes. These data established that the Worcester outbreak was caused by ET-5 complex meningococci which were not closely related to the ET-5 complex bacteria responsible for a hyperendemic outbreak in the nearby town of Stroud during the years preceding the Worcester outbreak. A comparison with other ET-5 complex meningococci established that there were at least three distinct globally distributed subpopulations within the ET-5 complex, characterized by particular housekeeping and antigen gene alleles. The Worcester isolates belonged to one of these subpopulations, the Stroud isolates belonged to another, and at least one representative of the third subpopulation identified in this work was isolated elsewhere in the United Kingdom. The sequence data demonstrated that ET-5 variants have arisen by multiple complex pathways involving the recombination of antigen and housekeeping genes and de novo mutation of antigen genes. The data further suggest that either the ET-5 complex has been in existence for many years, evolving and spreading relatively slowly until its disease-causing potential was recognized, or it has evolved and spread rapidly since its first identification in the 1970s, with each of the subpopulations attaining a distribution spanning several continents.
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Affiliation(s)
- J A Bygraves
- Division of Bacteriology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertsfordshire EN6 3QG, United Kingdom
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Kriz P, Giorgini D, Musilek M, Larribe M, Taha MK. Microevolution through DNA exchange among strains of Neisseria meningitidis isolated during an outbreak in the Czech Republic. Res Microbiol 1999; 150:273-80. [PMID: 10376489 DOI: 10.1016/s0923-2508(99)80052-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neisseria meningitidis is a highly variable bacterium. Indeed, N. meningitidis is naturally competent for transformation, and horizontal DNA exchange between strains may lead to mosaic genetic loci in N. meningitidis. We studied such an exchange in nature during an epidemic provoked by N. meningitidis. This epidemic started in the Czech Republic in 1993 and the original epidemic clone was shown to have the antigenic formula (serogroup:serotype:serosubtype) C:2a:P1.2,5. We analysed 145 meningococcal strains isolated in the Czech Republic between 1993 and 1997 using serological and genetic typing methods (multilocus enzyme electrophoresis and polymorphism of pilA and pilD genes). This analysis showed that genetic exchange between epidemic and endemic strains had occurred. Exchanges involved mostly surface-exposed structures such as the capsule, giving rise to new meningococcal variants. The expansion of these variants should be kept under close surveillance.
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Affiliation(s)
- P Kriz
- National Reference Laboratory for Meningococcal Infections, NIPH, Prague, Czech Republic
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Urwin R, Fox AJ, Musilek M, Kriz P, Maiden MC. Heterogeneity of the PorB protein in serotype 22 Neisseria meningitidis. J Clin Microbiol 1998; 36:3680-2. [PMID: 9817895 PMCID: PMC105262 DOI: 10.1128/jcm.36.12.3680-3682.1998] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/1998] [Accepted: 08/25/1998] [Indexed: 11/20/2022] Open
Abstract
The genetic diversity of porB genes from meningococcal isolates characterized as serotype 22 was investigated by gene sequencing. This procedure identified seven distinct porB sequences, demonstrating variation in the PorB protein recognized by the serotype 22 monoclonal antibody. This is consistent with the genetic heterogeneity of serotype 22 meningococci reported previously.
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Affiliation(s)
- R Urwin
- Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
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37
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Abstract
Penicillin resistance in clinical isolates of Streptococcus pneumoniae is mediated by mosaic genes encoding altered penicillin binding proteins. Mosaic sequence blocks are the result of a genetic exchange between related streptococcal species. It is likely that resistance has emerged in commensal streptococci before being transferred into the pneumococcus. Closely related mosaic genes are found in different pneumococcal clones and in different streptococcal species isolated worldwide since the first reports on such strains in the late 70s, demonstrating the importance of commensal streptococci for the spread of selectable markers in naturally transforming pathogens.
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38
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Abstract
Most models for coevolution of hosts and parasites are based on the assumption that resistance of hosts to parasites is an all-or-nothing effect. In many cases, for example where parasites require an appropriate receptor on host cells, this is a reasonable assumption. However, in many other cases, for example where hosts mount an immune response, this picture may be too simple. An immune system is expensive to maintain, which poses a question as to how much of its resources a host should allocate to resist parasites: if the risk of infection is low, natural selection may favour hosts with less effective immune systems. As optimal allocation to defence will depend on the force of infection, and the force of infection, in turn, depends on the level of defence in the rest of the host population, a game-theoretic approach is necessary. Here I analyse a simple model for the evolution of the ability to recover from infection. If parasites are not allowed to coevolve, the outcome is a single evolutionarily stable strategy (ESS). If the parasites coevolve, multiple evolutionary outcomes are possible, one in which the parasites are relatively avirulent and common and the hosts invest little in recovery ability, and another (the escalated arms race) where parasites are rare but virulent and the hosts invest heavily in defence.
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Affiliation(s)
- M van Baalen
- University of Warwick, Ecosystems Analysis and Management Group, Coventry, UK
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Abstract
Helicobacter pylori persists chronically within individuals and as they spread the mutating bacteria migrate with them. The continuous selection and microevolution generates a population of closely related but different bacteria that behave like a quasi-species. Within this heterogeneity, H. pylori strains fall into distinct types, into the virulent (type I) and less virulent (type II) strains, based on the presence of a pathogenicity island (cag) that encodes a specialized secretion machinery. We propose that during chronic infection a dynamic equilibrium between bacteria expressing a disparate degree of virulence is established, and that diverse forms prevail at different times.
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Affiliation(s)
- A Covacci
- Department of Molecular Biology, Immunobiological Research Institute ofSiena (IRIS), Chiron Vaccines, Via Fiorentina 1, 53100 Siena, Italy.
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40
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Rokbi B, Mignon M, Caugant DA, Quentin-Millet MJ. Heterogeneity of tbpB, the transferrin-binding protein B gene, among serogroup B Neisseria meningitidis strains of the ET-5 complex. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1997; 4:522-9. [PMID: 9302199 PMCID: PMC170586 DOI: 10.1128/cdli.4.5.522-529.1997] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
ET-5 complex strains of Neisseria meningitidis were traced intercontinentally and have been causing hyperendemic meningitis on a worldwide scale. In an attempt to develop a fully broad cross-reactive transferrin-binding protein B (TbpB)-based vaccine, we undertook to assess the extent of variability of TbpB proteins among strains of this epidemiological complex. For this purpose, a PCR-based method was developed to study the heterogeneity of the tbpB genes from 31 serogroup B N. meningitidis strains belonging to the ET-5 complex. To define adequate primers, the tbpB gene from an ET-5 complex strain, 8680 (B:15:P1.3; isolated in Chile in 1987), was cloned and the nucleotide sequence was determined and compared to two other previously published tbpB sequences. A tbpB fragment was amplified from genomic DNA from each of the 31 strains. By this method, heterogeneity in size was observed and further characterized by restriction pattern analysis with four restriction enzymes and by sequencing tbpB genes from three other ET-5 complex strains. Four distinct tbpB gene types were identified. Fifty-five percent of the strains studied (17/31) harbored tbpB genes similar to that of strain BZ83 (B:15:-) isolated in The Netherlands in 1984. Ten of the 31 strains (32.2%) had tbpB genes close to that of strain M982. Only 3 of the 31 (9.6%) were found to harbor tbpB genes close to that of strain 8680, and finally one strain, 8710 (B:15:P1.3; isolated in Chile in 1987), was found to harbor a tbpB gene different from all the others. These results demonstrated a pronounced variability among tbpB alleles within a limited number of ET-5 complex strains collected over a 19-year period. Despite the genetic heterogeneity observed, specific antisera raised to purified Tbps from ET-5 complex strains showed broad cross-reactivity between different TbpBs both by Western blot analysis and bactericidal assay, confirming that a limited number of TbpB molecules included in a vaccine are likely to induce broadly cross-reactive antibodies against the different strains.
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Affiliation(s)
- B Rokbi
- Pasteur Merieux Connaught, Marcy-l'Etoile, France
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42
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Aho EL, Botten JW, Hall RJ, Larson MK, Ness JK. Characterization of a class II pilin expression locus from Neisseria meningitidis: evidence for increased diversity among pilin genes in pathogenic Neisseria species. Infect Immun 1997; 65:2613-20. [PMID: 9199428 PMCID: PMC175370 DOI: 10.1128/iai.65.7.2613-2620.1997] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Strains of Neisseria meningitidis elaborate one of two classes of pili. Meningococcal class I pili have many features in common with pili produced by N. gonorrhoeae, including the ability to bind monoclonal antibody SM1 and a common gene and protein structure consisting of conserved, semivariable, and hypervariable regions. Class II pili are SM1 nonreactive and display smaller subunit molecular weights than do gonococcal or meningococcal class I pili. In this study, we have determined the N-terminal amino acid sequence for class II pilin and isolated the expression locus encoding class II pilin from N. meningitidis FAM18. Meningococcal class II pilin displays features typical of type IV pili and shares extensive amino acid identity with the N-terminal conserved regions of other neisserial pilin proteins. However, the deduced class II pilin sequence displays several unique features compared with previously reported meningococcal class I and gonococcal pilin sequences. Class II pilin lacks several conserved peptide regions found within the semivariable and hypervariable regions of other neisserial pilins and displays a large deletion in a hypervariable region of the protein believed to be exposed on the pilus face in gonococcal pili. DNA sequence comparisons within all three regions of the coding sequence also suggest that the meningococcal class II pilin gene is the most dissimilar of the three types of neisserial pilE loci. Additionally, the class II locus fails to display flanking-sequence homology to class I and gonococcal genes and lacks a downstream Sma/Cla repeat sequence, a feature present in all other neisserial pilin genes examined to date. These data indicate meningococcal class II pili represent a structurally distinct class of pili and suggest that relationships among pilin genes in pathogenic Neisseria do not necessarily follow species boundaries.
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Affiliation(s)
- E L Aho
- Department of Biology, Concordia College, Moorhead, Minnesota 56562, USA.
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Feil E, Zhou J, Maynard Smith J, Spratt BG. A comparison of the nucleotide sequences of the adk and recA genes of pathogenic and commensal Neisseria species: evidence for extensive interspecies recombination within adk. J Mol Evol 1996; 43:631-40. [PMID: 8995060 DOI: 10.1007/bf02202111] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The sequences of the adenylate kinase gene (adk) and the RecA gene (recA) were determined from the same isolates of Neisseria gonorrhoeae, N. meningitidis, N. lactamica, N. polysaccharea, N. cinerea, N. mucosa, N. pharyngis var. flava, N. flavescens, and N. animalis. The patterns of sequence divergence observed at adk and recA were very different. Dendrograms constructed from the recA data using two different algorithms were statistically robust and were congruent with each other and with the relationships between the species previously proposed using other data. In contrast, the dendrograms derived from the adk data were noncogruent with each other, and with those from the recA data, and were statistically poorly supported. These results, along with the uniform distribution of pairwise sequence divergences between the species at adk, suggest there has been a history of interspecies recombination within the adk gene of the human Neisseria species which has obscured the phylogenetic relationships between the species. This view was supported by Sawyer's runs test, and the Index of Association (IA) between codons, which provided significant evidence for interspecies recombination between the adk genes from the human Neisseria species, but no evidence of interspecies recombination between the recA sequences.
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Affiliation(s)
- E Feil
- School of Biological Sciences, University of Sussex, Falmer, Brighton, U.K
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44
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Bacterial species and evolution: Theoretical and practical perspectives. J Ind Microbiol Biotechnol 1996. [DOI: 10.1007/bf01574687] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Swaminathan B, Matar GM, Reeves MW, Graves LM, Ajello G, Bibb WF, Helsel LO, Morales M, Dronavalli H, el-Swify M, DeWitt W, Hunter SB. Molecular subtyping of Neisseria meningitidis serogroup B: comparison of five methods. J Clin Microbiol 1996; 34:1468-73. [PMID: 8735100 PMCID: PMC229044 DOI: 10.1128/jcm.34.6.1468-1473.1996] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In order to compare methods for subtyping Neisseria meningitidis serogroup B isolates, 96 isolates obtained from various locations in the United States and northwestern Europe were subtyped by five methods: monoclonal antibody (MAb)-based serotyping and serosubtyping, DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE), multilocus enzyme electrophoresis (MEE), ribotyping, and PCR-restriction fragment length polymorphism of the internally transcribed spacer region of the rRNA operon (ITS PCR-RFLP). All N. meningitidis serogroup B isolates were typeable by PFGE, MEE, ribotyping, and ITS PCR-RFLP. Only 44.8% of the isolates were completely typeable (both serotype and serosubtype determination) by MAb-based serotyping and serosubtyping. 60.4% of the isolates could be serotyped but not serosubtyped, and 90.6% of the isolates could be either serotyped or serosubtyped. Simpson's discrimination indices of diversity for the methods were as follows: PFGE, 99.7%; MEE, 99.4%; ribotyping, 98.8%; MAb serotyping, 75.8%; MAb serotyping and/or serosubtyping 97.5%; and ITS PCR-RFLP, 84.2%. The high degree of diversity observed by PFGE, MEE, and ribotyping can be explained by the fact that isolates were collected from different geographic locations at various times. PFGE, MEE, and ribotyping showed greater discriminatory abilities than MAb-based serotyping and serosubtyping or ITS PCR-RFLP.
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Affiliation(s)
- B Swaminathan
- Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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46
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Gupta S, Maiden MC, Feavers IM, Nee S, May RM, Anderson RM. The maintenance of strain structure in populations of recombining infectious agents. Nat Med 1996; 2:437-42. [PMID: 8597954 DOI: 10.1038/nm0496-437] [Citation(s) in RCA: 205] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Using mathematical models that combine population genetic and epidemiological processes, we resolve the paradox that many important pathogens appear to persist as discrete strains despite the constant exchange of genetic material. We show that dominant polymorphic determinants (that is, those that elicit the most effective immune responses) will be organized into nonoverlapping combinations as a result of selection by the host immune system, thereby defining a set of discrete independently transmitted strains. By analysing 222 isolates of Neisseria meningitidis, we show that two highly polymorphic epitopes of the outer membrane protein PorA exist in nonoverlapping combinations as predicted by this general framework. The model indicates that dominant polymorphic determinants will be in linkage disequilibrium, despite frequent genetic exchange, even though they may be encoded by several unlinked genes. This suggests that the detection of nonrandom associations between epitope regions can be employed as a novel strategem for identifying dominant polymorphic antigens.
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Affiliation(s)
- S Gupta
- Wellcome Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, Oxford, UK
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47
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Verdú ME, Coll P, Fontanals D, March F, Pons I, Sanfeliu I, Prats G. Endemic meningococcal disease in Cerdanyola, Spain, 1987--93: molecular epidemiology of the isolates of Neisseria meningitidis. Clin Microbiol Infect 1996; 2:168-178. [PMID: 11866840 DOI: 10.1016/s1198-743x(14)65139-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE: To establish the relationships between 30 Neisseria meningitidis strains isolated in Cerdanyola (Spain) from 30 out of 36 sporadic cases of meningococcal disease (MD) during 1987--93 and their spread in this population by multilocus enzyme electrophoresis (MEE) and by pulsed-field gel electrophoresis (PFGE), and to evaluate the usefulness of PFGE versus serologic typing methods and MEE as an alternative epidemiologic marker to study meningococcal infection. METHODS: Serotyping, electrophoretic mobility of seven isoenzymes determined by MEE and chromosomal DNA macrorestriction with NheI resolved by PFGE were analyzed. RESULTS: Of these 30 strains, 25 were serogroup B and the remaining five were serogroup C, with the 4:P1.15 and the 2b:NT as the most common antigenic phenotypes, respectively. There were 13 electrophoretic types (ETs) by MEE, with 14 isolates showing an identical ET, 8. Sixteen pulse types (PTs) were generated by PFGE. The 14 ET 8 isolates were clustered into six PTs, A1, A2, A4, A5, A6 and A8. However, by combining both methods, 19 genetically distinct groups were obtained. Eleven of these groups (20 serogroup B strains) and two of these (four serogroup C strains) were genetically related. CONCLUSIONS: We conclude that, according to the clonal population structure, these 30 N. meningitidis strains are heterogeneous although a great number are related. Moreover, PFGE is a useful method to establish clonal structure in N. meningitidis strains under endemic conditions. Finer discrimination of these strains was achieved by combining both MEE and PFGE methods.
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Affiliation(s)
- M. Esther Verdú
- Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
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48
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Feil E, Carpenter G, Spratt BG. Electrophoretic variation in adenylate kinase of Neisseria meningitidis is due to inter- and intraspecies recombination. Proc Natl Acad Sci U S A 1995; 92:10535-9. [PMID: 7479835 PMCID: PMC40646 DOI: 10.1073/pnas.92.23.10535] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In prokaryotic and eukaryotic organisms, the electrophoretic variation in housekeeping enzymes from natural populations is assumed to have arisen by the accumulation of stochastic predominantly neutral mutations. In the naturally transformable bacterium Neisseria meningitidis, we show that variation in the electrophoretic mobility of adenylate kinase is due to inter- and intraspecies recombination rather than mutation. The nucleotide sequences of the adenylate kinase gene (adk) from isolates that express the predominant slow electrophoretic variant were rather uniform, differing in sequence at an average of 1.1% of nucleotide sites. The adk sequences of rare isolates expressing the fast migrating variant were identical to each other but had a striking mosaic structure when compared to the adk genes from strains expressing the predominant variant. Thus the sequence from the fast variants was identical to those of typical slow variants in the first 158 bp of the gene but differed by 8.4% in the rest of the gene (nt 159-636). The fast electrophoretic variant appears to have arisen by the replacement of most of the meningococcal gene with the corresponding region from the adk gene of a closely related Neisseria species. The adk genes expressing the electrophoretic variant with intermediate mobility were perfect, or almost perfect, recombinants between the adk genes expressing the fast and slow variants. Recombination may, therefore, play a major role in the generation of electrophoretically detectable variation in housekeeping enzymes of some bacterial species.
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Affiliation(s)
- E Feil
- Molecular Microbiology Group, School of Biological Sciences, University of Sussex, Falmer, Brighton, United Kingdom
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49
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Dempsey JA, Wallace AB, Cannon JG. The physical map of the chromosome of a serogroup A strain of Neisseria meningitidis shows complex rearrangements relative to the chromosomes of the two mapped strains of the closely related species N. gonorrhoeae. J Bacteriol 1995; 177:6390-400. [PMID: 7592413 PMCID: PMC177488 DOI: 10.1128/jb.177.22.6390-6400.1995] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A physical map of the chromosome of N. meningitidis Z2491 (serogroup A, subgroup IV-1) has been constructed. Z2491 DNA was digested with NheI, SpeI, SgfI, PacI, BglII, or PmeI, resulting in a limited number of fragments that were resolved by contour-clamped homogeneous electric field (CHEF) electrophoresis. The estimated genome size for this strain was 2,226 kb. To construct the map, probes corresponding to single-copy genes or sequences were used on Southern blots of chromosomal DNA digested with the different mapping enzymes and subjected to CHEF electrophoresis. By determining which fragments from different digests hybridized to each specific probe, it was possible to walk back and forth between digests to form a circular macrorestriction map. The intervals between mapped restriction sites range from 10 to 143 kb in size. A total of 117 markers have been placed on the map; 75 represent identified genes, with the remaining markers defined by anonymous cloned fragments of neisserial DNA. Comparison of the arrangement of genetic loci in Z2491 with that in gonococcal strain FA1090, for which a physical map was previously constructed, revealed complex genomic rearrangements between the two strains. Although gene order is generally conserved over much of the chromosome, a region of approximately 500 kb shows translocation and/or inversion of multiple blocks of markers between the two strains. Even within the relatively conserved portions of the maps, several genetic markers are in different positions in Z2491 and FA1090.
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Affiliation(s)
- J A Dempsey
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill 27599, USA
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50
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Wedege E, Kolberg J, Delvig A, Høiby EA, Holten E, Rosenqvist E, Caugant DA. Emergence of a new virulent clone within the electrophoretic type 5 complex of serogroup B meningococci in Norway. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:314-21. [PMID: 7664178 PMCID: PMC170152 DOI: 10.1128/cdli.2.3.314-321.1995] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An increase in B:15:P1.12 meningococci among isolates from patients with Neisseria meningitidis infection in Norway in recent years led to further characterization of such strains. Between 1987 and 1992, B:15:P1.12 strains constituted 9.8% (24 strains) of B:15 isolates. The B:15:P1.12 strains belonged to the electrophoretic type 5 (ET-5) complex, but 17 (71%) strains were a new clone (ET-5c) not found elsewhere in the world. All but one strain of ET-5c were responsible for a localized outbreak of systemic meningococcal disease in western Norway. A novel monoclonal antibody (202,G-12), developed against the unknown variable region 2 on the class 1 protein of one of these strains, bound to 19 of the 15:P1.12 strains, 4 strains bound the subtype P1.13 reference monoclonal antibody MN24H10.75, and the remaining strain showed no reaction. Sequencing of porA genes demonstrated a series of nine threonine residues in the deduced variable region 2 of the latter strain, while four and five threonine residues were found in the corresponding regions of strains reacting with the monoclonal antibodies 202,G-12 and MN24H10.75, respectively. Epitope mapping with synthetic peptides showed that 202,G-12 bound to a sequence of 11 amino acids which included the four threonine residues specific for subtype P1.13a. Immunoglobulin G antibodies against the P1.7,16 subtype protein, induced in volunteers after vaccination with the Norwegian meningococcal vaccine, did not cross-react on immunoblots with the subtype protein of clone ET-5c. Thus, postvaccination class 1 protein antibodies, assumed to be protective, may not be effective against infection with the new clone.
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Affiliation(s)
- E Wedege
- Department of Vaccine, National Institute of Public Health, Oslo, Norway
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