title: Emergence of Streptococcus pneumoniae serogroups 15 and 35 in nasopharyngeal cultures from young children with acute otitis media.
abstract: BACKGROUND
  Surveillance of children with acute otitis media (AOM) for nasopharyngeal colonization with Streptococcus pneumoniae before, during and after the introduction of 7-valent pneumococcal conjugate vaccine (PCV7) indicated the near-complete elimination of PCV7 strains and the emergence of pneumococcal serotype 19A.
  
  
  METHODS
  To determine effects of the introduction of 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal nasopharyngeal colonization, we obtained nasopharyngeal cultures from 228 children 6 through 23 of age months presenting with a new episode of AOM during 2012 and 2013 and enrolled in an ongoing clinical trial of antimicrobial efficacy. All children had received at least 2 doses of PCV13. The S. pneumoniae isolates were subjected to serotyping and testing for antimicrobial susceptibility. We compared the findings with results obtained in 3 earlier studies.
  
  
  RESULTS
  We found nasopharyngeal colonization with S. pneumoniae in 113 (50%) of the children with AOM. PCV7 and PCV13 serotypes accounted for 2% and 12%, respectively, of the pneumococcal isolates. Of the 14 PCV13 isolates, 8 were serotype 19A. Nonvaccine serotypes accounted for 69% of the isolates. Most frequently occurring were subtypes of serotype 15 (23%) and serotype 35B (9%). Overall, 33% of the isolates were penicillin nonsusceptible, a proportion not significantly different from proportions found in our 3 earlier studies (26%, 36% and 37%, respectively). Serotypes 15 and 35B accounted for 51% of penicillin-nonsusceptible isolates.
  
  
  CONCLUSIONS
  Expansion of contents of pneumococcal vaccine administered to children is followed by not-fully-predictable changes in nasopharyngeal pneumococcal colonization. Continued surveillance is required to help inform future vaccine development.
authors.affiliation: From the *Department of Pediatrics, University of Pittsburgh School of Medicine and Children's Hospital of Pittsburgh, Divisions of General Academic Pediatrics and Infectious Disease, University of Pittsburgh, Pittsburgh, PA; and †Kentucky Pediatric Research Inc., Bardstown, KY.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Martin
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hoberman
authors.forename: Jack L
authors.initials: JL
authors.lastname: Paradise
authors.forename: Karen A
authors.initials: KA
authors.lastname: Barbadora
authors.forename: Nader
authors.initials: N
authors.lastname: Shaikh
authors.forename: Sonika
authors.initials: S
authors.lastname: Bhatnagar
authors.forename: Timothy
authors.initials: T
authors.lastname: Shope
authors.forename: Stan L
authors.initials: SL
authors.lastname: Block
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Haralam
authors.forename: Marcia
authors.initials: M
authors.lastname: Kurs-Lasky
authors.forename: D Kathleen
authors.initials: DK
authors.lastname: Colborn
authors.forename: Michael
authors.initials: M
authors.lastname: Green
mesh_terms: D000208:Acute Disease; D002353:Carrier State / Q000382:microbiology*; D052978:Disk Diffusion Antimicrobial Tests; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D010033:Otitis Media / Q000382:microbiology*; D010403:Penicillin Resistance; D011008:Pneumococcal Infections / Q000382:microbiology*; D022242:Pneumococcal Vaccines; D065288:Serogroup; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification
chemical_list: C538862:13-valent pneumococcal vaccine; D022242:Pneumococcal Vaccines