title: The epidemic wave of meningococcal disease in Spain in 1996-1997: probably a consequence of strain displacement.
abstract: During 1996 and 1997 an epidemic wave of meningococcal disease took place in Spain. Initial studies described the antigenic expression of the epidemic strain as C:2b:P1.2,5 and proposed that it was a variant of the previously identified Spanish C:2b:non-subtypable epidemic strain. To clarify this hypothesis, 1036 C:2b:P1.2(5) and 76 C:2b:NST isolates obtained during 1992-1999 were analysed by pulsed-field gel electrophoresis. The majority of the C:2b:P1.2,5 and C:2b:P1.2 isolates showed one of two very closely related profiles. During the epidemic period, 80% of the C:2b:NST strains showed these two pulsotypes. However, before the epidemic wave, most of these C:2b:NST strains (60%) showed a profile that was found infrequently among C:2b:P1.2,5 and C:2b:P1.2 isolates. A similar evolution was observed in C:2b:P1.5 isolates. Thirty-four C:2b:P1.2(5) and 10 C:2b:NST isolates, exhibiting representative pulsotypes, were subjected to multi-locus sequence typing. Isolates belonging to both A4 and ET-37 lineages were identified. These data point to the possibility that the A4 cluster has displaced the ET-37 complex among serogroup C meningococci in Spain.
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Alcalá
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Salcedo
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Arreaza
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Berrón
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: L DE LA
authors.initials: L
authors.lastname: Fuente
authors.affiliation: Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Vázquez
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D006801:Humans; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D017720:Molecular Epidemiology; D009345:Neisseria meningitidis / Q000145:classification / Q000235:genetics*; D012703:Serotyping; D013030:Spain / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial