Bacteria-mucin interaction in the upper aerodigestive tract shows striking heterogeneity: Implications in otitis media, rhinosinusitis, and pneumonia

The mucociliary system of the upper and lower respiratory tracts is a critical nonspecific pathway for the elimination of bacteria and other particulate matter. The interaction between bacteria and purified mucin of the upper and lower respiratory tracts has been a major focus of our laboratory for the past decade. We have previously demonstrated that nontypable Haemophilus influenzae and Moraxella catarrhalis adhere to human purified nasopharyngeal mucin and human middle ear mucin by a very limited number of specific outer membrane proteins. There have been no previous studies on the interaction of Streptococcus pneumoniae and purified mucin. Such information would be of extreme importance in identifying specific mechanisms of preventing colonization of this important pathogen to nasopharyngeal mucin. Using an overlay technique of purified radiolabeled mucins of the upper and lower respiratory tracts in a solid phase assay with 4 predominant pathogens of the upper and lower respiratory tracts, we found a striking heterogeneity of bacteria-mucin interaction. The implications of these interactions in the development of otitis media, rhinosinusitis, and lower respiratory infections are briefly discussed.