摘要Background:Acute otitis media (AOM) is an inflammatory disease of the middle ear causing significant morbidity in early childhood.A pilot study was undertaken to identify the role of various risk factors South Indian children with AOM,especially the role of nasopharyngeal otopathogens.Methodology:A prospective case control pilot study was conducted in children aged below six years,presenting to a single tertiary care from 2018 to 2019.Fifty cases with AOM and 45 age and gender matched controls were recruited.Two nasopharyngeal swabs were collected,one was processed for bacterial culture.The other swab was processed according to the CDC recommended broth enrichment method to identify carriage of S.pneumoniae.Subsequent serotyping was done by Quellung method and conventional sequential multiplex PCR.Result:Otalgia was the major presentation seen in 92％ of the children with AOM.None of the clinical and demographic characteristics were found to be statistically significant between the cases and controls.The most common otopathogen was S.pneumoniae (55％) followed by H.influenza (29％).The common S.pneumoniae serotypes encountered were llA and 19F.Nasopharyngeal colonization with S.pneumoniae[OR 6.57,p ＜ 0.003]and H.influenzae[OR14.18,p ＜ 0.003]were significant risk factors for AOM in children.The risk increased with co-colonization (OR 13.89,p ＜ 0.003).Conclusion:This study strengthens the significant association between nasopharyngeal colonization of otopathogens and AOM as a risk factor that is enhanced by co-colonization.S.pneumoniae was the main otopathogen in this population,serotypes 11A and 19F being the most common.