title: Multinational study of pneumococcal serotypes causing acute otitis media in children.
abstract: BACKGROUND
  Streptococcus pneumoniae is a major cause of acute otitis media (AOM) in young children. More than 90 immunologically distinct pneumococcal serotypes have been identified, but limited information is available regarding their relative importance in AOM.
  
  
  METHODS
  We analyzed nine existing datasets comprising pneumococcal isolates from middle ear fluid samples collected from 1994 through 2000 from 3,232 children with AOM from Finland, France, Greece, Israel, several East European countries, the US and Argentina. We examined the distribution of pneumococcal serotypes in relation to several demographic and epidemiologic variables, including gender, age, antibiotic resistance and source of culture material.
  
  
  RESULTS
  The major serotypes identified included 19F and 23F, each comprising 13 to 25% of pneumococcal middle ear fluid isolates in most datasets; 14 and 6B, comprising 6 to 18%; whereas 6A, 19A and 9V each comprised 5 to 10%. Despite differences in location, study design and antibiotic susceptibility, each major serotype was prominent in most age groups of each dataset. Serotypes represented in the 7-valent pneumococcal conjugate vaccine (PCV-7, 4, 6B, 9V, 14, 18C, 19F, 23F) accounted for 60 to 70% of all pneumococcal isolates in the 6- to 59-month age range, but only 40 to 50% of isolates in children <6 or >/=60 months old. Serotype 3 and, in certain datasets, serotypes 1 and 5, were more important in the <6- and >/=60-month age groups. In each age group vaccine-related serotypes (mainly 6A and 19A) comprised an additional 10 to 15% of all pneumococcal isolates. Four serotypes (23F, 19F, 14 and 6B) accounted for 83% of all penicillin-resistant observations.
  
  
  CONCLUSIONS
  This analysis of several geographically diverse datasets indicates that a limited number of serotypes, largely represented in PCV-7, accounted for the majority of episodes of pneumococcal AOM in children between 6 and 59 months of age. Certain serotypes appeared to be relatively more significant in children <6 months or >59 months of age.
authors.affiliation: Wyeth Vaccines, West Henrietta, NY 14586, USA. Hausdowp@wyeth.com
authors.forename: William P
authors.initials: WP
authors.lastname: Hausdorff
authors.forename: Greg
authors.initials: G
authors.lastname: Yothers
authors.forename: Ron
authors.initials: R
authors.lastname: Dagan
authors.forename: Terhi
authors.initials: T
authors.lastname: Kilpi
authors.forename: Stephen I
authors.initials: SI
authors.lastname: Pelton
authors.forename: Robert
authors.initials: R
authors.lastname: Cohen
authors.forename: Michael R
authors.initials: MR
authors.lastname: Jacobs
authors.forename: Sheldon L
authors.initials: SL
authors.lastname: Kaplan
authors.forename: Corinne
authors.initials: C
authors.lastname: Levy
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Lopez
authors.forename: Edward O
authors.initials: EO
authors.lastname: Mason
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Syriopoulou
authors.forename: Brian
authors.initials: B
authors.lastname: Wynne
authors.forename: John
authors.initials: J
authors.lastname: Bryant
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010033:Otitis Media / Q000453:epidemiology / Q000382:microbiology*; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000276:immunology; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D010406:Penicillins; D022242:Pneumococcal Vaccines