Background: Acute otitis media (AOM) is one of the most common bacterial infections in childhood and the most frequent reason for antibiotic use. Bacterial conjugate vaccines have demonstrated some efficacy in preventing AOM, but impact may vary according to underlying pathogen and serotype distribution. Because data from Latin America are limited, this report provides novel data regarding bacterial etiology and serotypes of AOM cases within a routine clinical setting in two medical centers in Cali, Colombia to determine what proportion of disease may be vaccine-preventable. Methods: Children aged "3 months to <5 years with new episodes of AOM (onset of symptoms <3 days) were included. Middle ear fluid (MEF) samples were collected by tympanocentesis or by sampling of spontaneous otorrhea (<20% of all cases). Recovered bacteria were identified and serotyped. Results: 99 children with new episodes of AOM were enrolled between January 2008 and January 2009. 100 MEF samples from tympanocentesis (n = 84) and otorrhea (n = 16) were collected (1 subject had 1 sample collected in each ear). The median participant age was 29 months (range: 5 - 55months), and 54.5% of subjects were male. Bacteria were cultured from 63% samples with at least one pathogen under study. H. influenzae was isolated in 31 (31%), 30 S. pneumoniae (30%), 2 S. pyogenes (2%) and 3 S. aureus (3%). 14 (46.7%) S. pneumoniae isolates were serotypes found in the two licensed pneumococcal conjugate vaccines (14, 19F & 23F), 7 (23%) were vaccine-related types 6A (n = 5) and 19A (n = 2) and 7 were non-vaccine types. 27/31 (87%) of H. influenzae isolates were non-typeable. No M. catarrhalis was isolated. Conclusion: Non-typeable H. influenzae and S. pneumoniae were the leading bacterial causes of AOM in Cali, Colombia. A vaccine with efficacy against both pathogens would be most useful to prevent AOM. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive