title: Genotypic and phenotypic characterization of carriage and invasive disease isolates of Neisseria meningitidis in Finland.
abstract: The relationship between carriage and the development of invasive meningococcal disease is not fully understood. We investigated the changes in meningococcal carriage in 892 military recruits in Finland during a nonepidemic period (July 2004 to January 2006) and characterized all of the oropharyngeal meningococcal isolates obtained (n = 215) by using phenotypic (serogrouping and serotyping) and genotypic (porA typing and multilocus sequence typing) methods. For comparison, 84 invasive meningococcal disease strains isolated in Finland between January 2004 and February 2006 were also analyzed. The rate of meningococcal carriage was significantly higher at the end of military service than on arrival (18% versus 2.2%; P < 0.001). Seventy-four percent of serogroupable carriage isolates belonged to serogroup B, and 24% belonged to serogroup Y. Most carriage isolates belonged to the carriage-associated ST-60 clonal complex. However, 21.5% belonged to the hyperinvasive ST-41/44 clonal complex. Isolates belonging to the ST-23 clonal complex were cultured more often from oropharyngeal samples taken during the acute phase of respiratory infection than from samples taken at health examinations at the beginning and end of military service (odds ratio [OR], 6.7; 95% confidence interval [95% CI], 2.7 to 16.4). The ST-32 clonal complex was associated with meningococcal disease (OR, 17.8; 95% CI, 3.8 to 81.2), while the ST-60 clonal complex was associated with carriage (OR, 10.7; 95% CI, 3.3 to 35.2). These findings point to the importance of meningococcal vaccination for military recruits and also to the need for an efficacious vaccine against serogroup B isolates.
authors.affiliation: Institute of Diagnostics, Department of Medical Microbiology, University of Oulu, Oulu, Finland. ujounio@paju.oulu.fi
authors.forename: Ulla
authors.initials: U
authors.lastname: Jounio
authors.forename: Annika
authors.initials: A
authors.lastname: Saukkoriipi
authors.forename: Holly B
authors.initials: HB
authors.lastname: Bratcher
authors.forename: Aini
authors.initials: A
authors.lastname: Bloigu
authors.forename: Raija
authors.initials: R
authors.lastname: Juvonen
authors.forename: Sylvi
authors.initials: S
authors.lastname: Silvennoinen-Kassinen
authors.forename: Ari
authors.initials: A
authors.lastname: Peitso
authors.forename: Terttu
authors.initials: T
authors.lastname: Harju
authors.forename: Olli
authors.initials: O
authors.lastname: Vainio
authors.forename: Markku
authors.initials: M
authors.lastname: Kuusi
authors.forename: Martin C J
authors.initials: MC
authors.lastname: Maiden
authors.forename: Maija
authors.initials: M
authors.lastname: Leinonen
authors.forename: Helena
authors.initials: H
authors.lastname: Käyhty
authors.forename: Maija
authors.initials: M
authors.lastname: Toropainen
mesh_terms: D000293:Adolescent; D000328:Adult; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006805:Human Experimentation; D006801:Humans; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D008889:Military Personnel; D058885:Multilocus Sequence Typing; D009345:Neisseria meningitidis / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D009960:Oropharynx / Q000382:microbiology; D015995:Prevalence; D012703:Serotyping; D055815:Young Adult