title: Streptococcus pneumoniae colonization in the young child: association with otitis media and resistance to penicillin.
abstract: OBJECTIVE
  To determine the nasopharyngeal colonization rate of penicillin-susceptible and penicillin-resistant strains of Streptococcus pneumoniae in young children, and to assess its relationship with the incidence of otitis media.
  
  
  METHODS
  Observational study in 215 children younger than 6 years of age who received care in the Vanderbilt Vaccine Clinic from September 1, 1992, to August 31, 1993.
  
  
  RESULTS
  Of 842 nasopharyngeal cultures obtained, results for 44% of the cultures were positive for S. pneumoniae; 73% of the isolates were serotypes 6, 14, 19, or 23. Younger children had significantly higher rates of pneumococcal colonization than older children, with a peak at 1 year of age. By microdilution susceptibility testing, 37% of the cultures with positive results were intermediately or highly resistant to penicillin. Significantly more serotype 19 and 23 isolates were penicillin resistant than organisms of other serotypes. Children younger than 2 years of age had a twofold higher percentage of resistant isolates than those older than 2 years of age. A significant association was noted between nasopharyngeal carriage of S. pneumoniae and acute otitis media (p = 0.0002); however, the incidence of acute otitis media did not differ significantly between children colonized with penicillin-susceptible or penicillin-resistant strains. Unresolved otitis media was diagnosed more often in children who were colonized with resistant organisms than in children colonized with susceptible strains (p = 0.04).
  
  
  CONCLUSIONS
  There was a high rate of nasopharyngeal carriage of penicillin-resistant S. pneumoniae in this population of young children. Nasopharyngeal colonization was associated with an increased incidence of acute otitis media, and penicillin resistance was associated with an increased incidence of unresolved otitis media.
authors.affiliation: Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Zenni
authors.forename: S H
authors.initials: SH
authors.lastname: Cheatham
authors.forename: J M
authors.initials: JM
authors.lastname: Thompson
authors.forename: G W
authors.initials: GW
authors.lastname: Reed
authors.forename: A B
authors.initials: AB
authors.lastname: Batson
authors.forename: P S
authors.initials: PS
authors.lastname: Palmer
authors.forename: K L
authors.initials: KL
authors.lastname: Holland
authors.forename: K M
authors.initials: KM
authors.lastname: Edwards
mesh_terms: D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002675:Child, Preschool; D004352:Drug Resistance, Microbial; D006801:Humans; D007223:Infant; D009305:Nasopharynx / Q000382:microbiology; D010033:Otitis Media / Q000175:diagnosis / Q000209:etiology*; D010406:Penicillins / Q000627:therapeutic use*; D012703:Serotyping; D013290:Streptococcal Infections / Q000150:complications* / Q000188:drug therapy; D013296:Streptococcus pneumoniae / Q000302:isolation & purification* / Q000472:pathogenicity*
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins