Related Experiment Videos
[Clonal spread of Neisseria meningitidis W135]
M K Taha1, A Antignac, P Renault
1Unité des Neisseria, Département de Bactérologie et de Mycologie Centre National de Référence des Méningocoques Institut Pasteur, 25-28 rue du Dr Roux, F75724 Paris. mktaha@pasteur.fr
Objectives:
Efficient surveillance of communicable diseases involves dose collaboration between physicians, epidemiologist and bacteriologists. The characterization of meningococcal infections is a medical emergency due to their lethality and their epidemic behavior. The recent expansion of Neisseria meningitidis of serogroup W135 among pilgrims and their contacts underlines the need of a multidisciplinary procedure of alert.
Methods:
Meningococcal strains are usually received by the National Reference Center for Meningococci (CNRM). They are identified and then typed to determine their antigenic formula (serogroup:serotype:serosubtype). For cluster analysis, the CNRM as well as the WHO collaborating center, perform molecular typing of isolated strains. Should an epidemic is suspected, the institut de Veille Sanitaire and the Direction Générale de la Santé are immediately informed.
Results:
Between the 22th of March and the 20th of November 2000, 27 cases of systemic meningococcal infections due to N. meningitidis of the antigenic formula W135:2a:P1-2.5 were identified. Molecular typing of these strains showed that they were clonal and belonged to the complex ET-37. The dissemination of this clone among pilgrims who were vaccinated against serogroups A and C may suggest the selection of a new variant by an escape alteration in the capsule. However, such strains were detected in France as early as 1994.
Conclusion:
The global spread of N. meningitidis of serogroup W135 belonging to the ET-37 clonal complex should be kept under a close surveillance since epidemics may occur particularly in Africa. New vaccination procedures (quadrivalent vaccines and multivalent conjugate meningococcal vaccines) are therefore needed.
Insights
The Neisseria meningitidis W135 strain, part of the ET-37 clonal complex, caused systemic infections in 2000. Close surveillance is crucial, especially in Africa, due to potential epidemic spread and the need for updated meningococcal vaccines.
Area of Science:
- Medical microbiology
- Epidemiology
- Public health surveillance
Background:
- Neisseria meningitidis infections are a medical emergency due to high lethality and epidemic potential.
- The emergence of serogroup W135 strains, particularly among pilgrims, necessitates enhanced surveillance and multidisciplinary response.
- Efficient disease surveillance relies on collaboration between physicians, epidemiologists, and bacteriologists.
Purpose of the Study:
- To characterize Neisseria meningitidis strains identified during a specific period.
- To investigate the clonal nature and antigenic formula of emerging meningococcal isolates.
- To inform public health strategies for controlling meningococcal disease outbreaks.
Main Methods:
- Collection and identification of meningococcal strains by the National Reference Center for Meningococci (CNRM).
- Serotyping and molecular typing (including cluster analysis) of isolated strains.
- Notification of public health authorities (Institut de Veille Sanitaire, Direction Générale de la Santé) upon suspicion of an epidemic.
Main Results:
- Twenty-seven cases of systemic meningococcal infections caused by N. meningitidis W135:2a:P1-2.5 were identified between March and November 2000.
- Molecular typing confirmed these strains were clonal and belonged to the ET-37 complex.
- The emergence of this clone in vaccinated pilgrims suggests potential capsule alteration, with similar strains detected in France since 1994.
Conclusions:
- The global spread of N. meningitidis W135 (ET-37 complex) requires continuous surveillance due to epidemic potential, especially in Africa.
- The findings highlight the need for updated vaccination strategies, including quadrivalent and multivalent conjugate meningococcal vaccines.
- Multidisciplinary collaboration is essential for effective control of meningococcal disease outbreaks.