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Salvatore P, Pagliarulo C, Colicchio R, Zecca P, Cantalupo G, Tredici M, Lavitola A, Bucci C, Bruni CB, Alifano P. Identification, characterization, and variable expression of a naturally occurring inhibitor protein of IS1106 transposase in clinical isolates of Neisseria meningitidis. Infect Immun 2001; 69:7425-36. [PMID: 11705917 PMCID: PMC98831 DOI: 10.1128/iai.69.12.7425-7436.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Transposition plays a role in the epidemiology and pathogenesis of Neisseria meningitidis. Insertion sequences are involved in reversible capsulation and insertional inactivation of virulence genes encoding outer membrane proteins. In this study, we have investigated and identified one way in which transposon IS1106 controls its own activity. We have characterized a naturally occurring protein (Tip) that inhibits the transposase. The inhibitor protein is a truncated version of the IS1106 transposase lacking the NH(2)-terminal DNA binding sequence, and it regulates transposition by competing with the transposase for binding to the outside ends of IS1106, as shown by gel shift and in vitro transposition assays. IS1106Tip mRNA is variably expressed among serogroup B meningococcal clinical isolates, and it is absent in most collection strains belonging to hypervirulent lineages.
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Affiliation(s)
- P Salvatore
- Dipartimento di Biologia e Patologia Cellulare e Molecolare "L. Califano," Università di Napoli "Federico II," Naples, Italy
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2
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Vogel U, Morelli G, Zurth K, Claus H, Kriener E, Achtman M, Frosch M. Necessity of molecular techniques to distinguish between Neisseria meningitidis strains isolated from patients with meningococcal disease and from their healthy contacts. J Clin Microbiol 1998; 36:2465-70. [PMID: 9705375 PMCID: PMC105145 DOI: 10.1128/jcm.36.9.2465-2470.1998] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serogroup C strains of Neisseria meningitidis were isolated from a Germany patient with severe meningococcal disease after a trip to the Czech Republic. These strains (case isolates) were characterized by classical and molecular techniques, as were other strains (carrier isolates) isolated from healthy contacts. Five of 10 carrier isolates had switched off the expression of capsular polysaccharide, as demonstrated by a serogroup-specific PCR. The two case isolates were indistinguishable by multilocus sequence typing and belonged to the ET-37 complex. The carrier isolates belonged to four different sequence types, all unrelated to that of the case strains. Pulsed-field gel electrophoresis showed that the case isolates differed from reference ET-37 complex strains from the Czech Republic and Canada as well as from all the carrier isolates. The isolate from the patient's nasopharynx was indistinguishable from the blood isolate except for a 40,000-bp chromosomal deletion that had occurred during systemic spread.
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Affiliation(s)
- U Vogel
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
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Newcombe J, Dyer S, Blackman L, Cartwright K, Palmer WH, McFadden J, Blackwell L. PCR-single-stranded confirmational polymorphism analysis for non-culture-based subtyping of meningococcal strains in clinical specimens. J Clin Microbiol 1997; 35:1809-12. [PMID: 9196199 PMCID: PMC229847 DOI: 10.1128/jcm.35.7.1809-1812.1997] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Subspecific typing of clinical meningococcal strains is important in the investigation of outbreaks and for disease surveillance. Serogrouping, typing, and subtyping of strains currently require isolation of a meningococcus from one or more clinical specimens. However, the increasing widespread practice of preadmission administration of parenteral antibiotics has resulted in a decrease in the frequency of positive cultures obtained from blood and cerebrospinal fluid. Confirmation of meningococcal disease can be obtained by meningococcus-specific PCR from both cerebrospinal fluid (H. Ni et al., Lancet 340:1432-1434, 1992) and peripheral blood (J. Newcombe et al., J. Clin. Microbiol. 34:1637-1640, 1996) specimens. However, current PCR protocols do not yield epidemiologically useful typing information. We report here the use of PCR-single-stranded confirmational polymorphism (PCR-SSCP) analysis to amplify and type meningococcal DNA present in clinical specimens. PCR-SSCP analysis with the VR1 region of the Neisseria meningitidis porA gene as the target produced unique banding patterns for each serosubtype. Direct PCR-SSCP of clinical specimens can therefore provide typing data that can be used to investigate the epidemiology of clusters of cases and outbreaks and for disease surveillance in situations in which culture of patient specimens proves negative.
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Affiliation(s)
- J Newcombe
- Molecular Microbiology Group, School of Biological Sciences, University of Surrey, Guildford, United Kingdom
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Zhu P, Hu X, Xu L. Typing Neisseria meningitidis by analysis of restriction fragment length polymorphisms in the gene encoding the class 1 outer membrane protein: application to assessment of epidemics throughout the last 4 decades in China. J Clin Microbiol 1995; 33:458-62. [PMID: 7714207 PMCID: PMC227966 DOI: 10.1128/jcm.33.2.458-462.1995] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A typing method was developed for Neisseria meningitidis serogroup A by analysis of restriction fragment length polymorphisms (RFLP) of the class 1 outer membrane protein gene (porA). By using appropriate primers, an approximately 1,116-bp fragment of the porA gene was amplified by PCR and then was digested with the restriction endonuclease MspI. The digestion products were separated on 10% polyacrylamide gels and were stained with silver. One hundred three clinical isolates of group A N. meningitidis from 17 provinces of China collected over a 26-year period were analyzed. Results of MspI-generated RFLP profiles of PCR-amplified porA genes were compared with those obtained by conventional serosubtyping. There was a band of about 400 bp common to all strains examined, and the 103 strains of serogroup A resulted in 22 unique RFLP patterns. The differences in bands could be observed mainly in the range of 120 to 280 bp. The smaller fragments were useful in distinguishing meningococci with the same serosubtype. Three epidemic periods were characterized by the presence of three distinct genotypes (a1, a2, and a3), accounting for 74.5% of the strains examined (3.88, 26.21, and 44.66%, respectively). Three predominant RFLP patterns were correlated epidemiologically with cycles of epidemic meningococcal meningitis and were well-matched to the predominant serosubtypes (P1.9, P1.7, 10, and P1.9) that presented at the same prevalence cycles. The genotyping yielded information that allowed strains from one epidemic to be distinguished from those from another that would have been indistinguishable if only serotyping and serosubtyping were available. Therefore, the PCR-RFLP typing method was very useful in the epidemiologic investigation of group A meningococcal meningitis.
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Affiliation(s)
- P Zhu
- Institute of Epidemiology and Microbiology, Chinese Academy of Preventive Medicine, Changping, Beijing
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Mylvaganam HAIMA, Gilja ODDHELGE, Halstensen ALFRED, HØIby EARNE, Digranes ASBJØRN, Bjorvatn BJARNE. Strain differentiation ofNeisseria meningitidisby small-fragment restriction endonuclease analysis (SF-REA). APMIS 1995. [DOI: 10.1111/j.1699-0463.1995.tb01090.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ni H, Knight AI, Cartwright KA, McFadden JJ. Phylogenetic and epidemiological analysis of Neisseria meningitidis using DNA probes. Epidemiol Infect 1992; 109:227-39. [PMID: 1356820 PMCID: PMC2271919 DOI: 10.1017/s0950268800050184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The genetic relationships between various serotypes and serogroups of meningococcal strains were investigated by restriction fragment-length polymorphism (RFLP) analysis using a number of random DNA probes and a probe containing a truncated copy of the meningococcal insertion sequence IS1106. The data were used to estimate genetic distance between all pairs of strains and to construct phylogenetic trees for meningococcal strains. B15:P1.16R strains isolated from cases of systemic meningococcal disease in two health districts with a high incidence of disease were clonal in contrast to similar strains from cases occurring in other parts of the UK. Strains from these areas, which contain a similar genomic deletion, were found to be derived from two distinct lineages within the B15:P1.16R phylogenetic group. RFLP data demonstrated that present serological typing systems for the meningococcus do not necessarily reflect true genetic relationships.
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Affiliation(s)
- H Ni
- Molecular Microbiology Group, School of Biological Sciences, University of Surrey, Guildford, UK
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Rådström P, Fermér C, Kristiansen BE, Jenkins A, Sköld O, Swedberg G. Transformational exchanges in the dihydropteroate synthase gene of Neisseria meningitidis: a novel mechanism for acquisition of sulfonamide resistance. J Bacteriol 1992; 174:6386-93. [PMID: 1400191 PMCID: PMC207587 DOI: 10.1128/jb.174.20.6386-6393.1992] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The nucleotide sequences of the chromosomal dihydropteroate synthase (dhps) genes in sulfonamide-susceptible and sulfonamide-resistant strains of Neisseria meningitidis of serogroups A, B and C were determined. The molecular weights and the amino acid sequences showed similarity to those of all other known dihydropteroate synthase polypeptides. Sequence comparison of the N. meningitidis dhps genes indicated horizontal transfer of DNA segments rather than point mutations as the cause for resistance in meningococci. The dhps genes in three of four sulfonamide-resistant meningococci contained identical central regions of 424 bp. Compared with the corresponding genes in susceptible strains, each central region included an insert of 6 bp. In one of the sulfonamide-resistant strains, the dhps gene was similar to the corresponding genes in the sensitive strains in its NH2-terminal and C-terminal parts. Its central region, however, was identical to the corresponding regions of two of the other resistant genes, and thus it could be seen as a hybrid dhps gene. Transformation experiments and mapping of transformed dhps genes indicated the existence of a novel mechanism for the dissemination of sulfonamide resistance in N. meningitidis. The origin of the resistance-mediating segment of the gene is unknown, but hybridization results showed the presence of homologous dhps genes in Neisseria gonorrhoeae and N. lactamica but not in N. subflava or Branhamella catarrhalis.
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Affiliation(s)
- P Rådström
- Chemical Center, Lund University, Sweden
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Knight AI, Ni H, Cartwright KA, McFadden JJ. Identification and characterization of a novel insertion sequence, IS1106, downstream of the porA gene in B15 Neisseria meningitidis. Mol Microbiol 1992; 6:1565-73. [PMID: 1320728 DOI: 10.1111/j.1365-2958.1992.tb00878.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Examination of Neisseria meningitidis strains associated with endemic meningococcal disease demonstrated differences in the number of copies of a repetitive sequence. Characterization of a copy of this repetitive sequence present in B15 strains has revealed the presence of a novel insertion sequence (IS1106) located within a complex repetitive region downstream of the gene for the major surface antigen (porA). IS1106 has a length of 1137 bp and is flanked by 36bp inverted repeats. Two open reading frames (ORF1 and ORF2) are present in opposite strands in codon-codon register with ORF2 entirely located within ORF1. The predicted protein from ORF1 demonstrates homology with the 5A protein of IS5 (Kroger and Hobom, 1982). Strains from two independent outbreaks of B15 meningococcal disease in the UK were found to contain the same genomic deletion removing a copy of IS1106 downstream of the porA gene.
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Affiliation(s)
- A I Knight
- School of Biological Sciences, University of Surrey, Guildford, UK
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Lew AE, Desmarchelier PM. Restriction fragment length polymorphism analysis of Listeria monocytogenes and its application to epidemiological investigations. Int J Food Microbiol 1992; 15:347-56. [PMID: 1358161 DOI: 10.1016/0168-1605(92)90068-e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The restriction fragment length polymorphisms (RFLPs) of 64 random and potentially related strains of Listeria monocytogenes were analysed and compared using a probe comprised of two L. monocytogenes chromosome fragments cloned into a lambda vector. Twelve RFLP types were defined using 14 isolates of clinical origin, 42 food isolates and eight food associated environmental strains. Of the RFLP types, some were common to a particular serovar and source, whereas others were widespread amongst all serovars and sources. One of the two most common RFLP patterns was associated with serovar 1/2 isolates from food or the environment, whereas another dominant pattern was associated most commonly with serovar four isolates from all sources. The potential relationships between epidemiologically related strains were examined, with the analysis of types from a suspected listeriosis outbreak, from clinical maternal-foetal cases, and from an ice-cream factory environmental study. Serotyping alone was not a sufficient marker for the comparison of these strains whereas further discrimination of strains was possible with RFLP analysis.
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Affiliation(s)
- A E Lew
- Tropical Health Program, University of Queensland, Brisbane, Australia
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McGuinness BT, Clarke IN, Lambden PR, Barlow AK, Poolman JT, Jones DM, Heckels JE. Point mutation in meningococcal por A gene associated with increased endemic disease. Lancet 1991; 337:514-7. [PMID: 1705642 DOI: 10.1016/0140-6736(91)91297-8] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The por A gene, which encodes expression of meningococcal class 1 outer membrane protein, responsible for antigenic subtype specificity, has been cloned and sequenced in an isolate of Neisseria meningitidis (B:15:P1.7,16) from a patient in the Gloucester area with meningococcal meningitis. Comparison of the sequence with that of the equivalent gene from the P1.7,16 reference strain reveals a point mutation which generates a single aminoacid change in the epitope responsible for P1.16 specificity. Monoclonal antibodies with P1.16 specificity do not react with synthetic peptides that correspond to the altered epitope, and do not promote complement-mediated bactericidal killing of the isolate. Analysis of other strains shows widespread distribution of infections due to B:15:P1.7,16 meningococci with the altered epitope (P1.16b) in England and Wales.
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Affiliation(s)
- B T McGuinness
- Department of Microbiology, University of Southampton Medical School, UK
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