title: Microbiology of otitis media in Costa Rican children, 1999 through 2001.
abstract: BACKGROUND
  Because of the increasing number of resistant middle ear pathogens and the impact of the new conjugate Streptococcus pneumoniae vaccine, an active surveillance of the microbiology and susceptibility pattern of middle ear pathogens is required.
  
  
  OBJECTIVE
  To study the microbiology and susceptibility pattern of middle ear pathogens obtained from Costa Rican children with acute otitis media (AOM), recurrent otitis media (ROM) and therapeutic failure otitis media (FOM).
  
  
  METHODS
  Between 1999 and 2001 middle ear fluid (MEF) was collected from 276 Costa Rican patients. S. pneumoniae serotyping and pulsed field gel electrophoresis analysis was done on available strains.
  
  
  RESULTS
  Among the total study population, 102 were AOM patients, 98 were ROM patients and 76 were FOM patients. Overall S. pneumoniae (88 strains) was the most common pathogen isolated followed by Haemophilus influenzae (41 strains) and Streptococcus pyogenes (10 strains). H. influenzae was the most common agent in FOM patients (P = 0.015). Beta-lactamase production was observed in 3 of 41 (7%) H. influenzae strains and 3 of 3 (100%) Moraxella catarrhalis strains. Penicillin-nonsusceptible S. pneumoniae strains were more common in FOM (64%) and ROM (63%) patients than in AOM (42%) patients (P = 0.05). S. pneumoniae serotype 19F was the most prevalent serotype, mainly within one distinct clone.
  
  
  CONCLUSIONS
  Overall S. pneumoniae serotype 19F was the most common isolate from the middle ear fluid of Costa Rican children. Beta-lactamase-negative H. influenzae was the most prevalent in the subpopulation of patients with FOM. S. pyogenes was the third most common isolate and M. catarrhalis was uncommon.
authors.affiliation: Instituto de Atención Pediátrica, San José, Costa Rica. aarguedas@iped.net
authors.forename: Adriano
authors.initials: A
authors.lastname: Arguedas
authors.forename: Ron
authors.initials: R
authors.lastname: Dagan
authors.forename: Carolina
authors.initials: C
authors.lastname: Soley
authors.forename: Cecilia
authors.initials: C
authors.lastname: Loaiza
authors.forename: Katherine
authors.initials: K
authors.lastname: Knudsen
authors.forename: Nurith
authors.initials: N
authors.lastname: Porat
authors.forename: Alexandra
authors.initials: A
authors.lastname: Pérez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Brilla
authors.forename: Marco Luis
authors.initials: ML
authors.lastname: Herrera
mesh_terms: D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003364:Costa Rica / Q000453:epidemiology; D004352:Drug Resistance, Microbial; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D010034:Otitis Media with Effusion / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D000900:Anti-Bacterial Agents