The value of nasopharyngeal culture in predicting the etiology of acute otitis media in children less than two years of age

Background: In selecting treatment of acute otitis media (AOM), knowledge of its etiology would be valuable. We revisited the possibility to use the nasopbaryngeal culture of Streptococcus pneumoniae (Pnc) and Haemophilus influenzae (Hi) for predicting their presence in the middle ear fluid (MEF) during AOM. Methods: The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of bacterial culture of the nasopharyngeal aspirate (NPA) in predicting the presence of the same pathogen in the MEF were assessed during AOM events among children followed from 2 to 24 months of age. Results: The data comprised 586 AOM events. For Pnc, the sensitivity and NPV were high, 99% (95% confidence interval = 95-100%) and > 99% (97-100%), respectively. The specificity and PPV were relatively low, 63% (57-68%) and 50% (43-56%). For Hi, the sensitivity and the NPV were lower (77%, 69-83% and 93%, 90-95%) than for Pnc, but the specificity and the PPV were higher (88%, 85-91% and 64%, 56-71%). The quantity of Pnc and Hi in the NPA was clearly related to their presence in the MEF. If both Pnc and Hi were found in the nasopharynx, Hi was more likely cultured from MEF. Conclusion: Together with clinical and epidemiologic features of AOM, the nasopharyngeal culture can be helpful in selecting specific antimicrobial therapy.