The nasopharyngeal bacterial flora in children with otitis media with effusion

A study was undertaken to evaluate the incidence of nasopharyngeal alpha-streptococci with inhibitory activity against pathogens, as a defense mechanism of the normal bacterial flora against infection. Cultures were taken from the nasopharynges of 43 children with otitis media with effusion (OME). The detection rates of alpha-streptococci with inhibitory activity against Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus and group A streptococci were significantly lower in the nasopharynx than those isolated from the tonsils of the same patients. Moreover, the detection rates of alpha-streptococci with inhibitory activity against all of these pathogens derived from the nasopharynx were lower than those in healthy children, streptococcal strains with activity against H. influenzae and Strep. pneumoniae were also lower than that in patients with tonsilitis. These findings suggest that low nasopharyngeal levels of alpha-streptococci with inhibitory activity against respiratory pathogens may render children susceptible to OME. Further studies are needed to investigate the relationships between the prevalence of pathogens in the nasopharynx and the inhibitory activities of alpha-streptococci against them in order to devise and select optimal treatment for patients with OME.