Antibody coated bacteria in otitis media with effusions.

The significance of bacterial isolates of coagulase negative Staphylococcus epidermidis and Corynebacterium species in middle ear fluids remains controversial. This study was undertaken to evaluate the possible role of these organisms in different effusions. Cultures were obtained from the external cartilaginous ear, bony canal, tympanic membrane, middle ear fluids, tonsils and nasopharynx of 93 patients at the time of myringotomy for otitis media with effusion. Isolates of coagulase negative staphylococci from the middle ear, external ear and posterior aural skin were evaluated in regard to antibiotic sensitivity, biochemical tests and phage typing. Furthermore, in another series of patients in whom these organisms were isolated, specific antibody activity in both middle ear washings and corresponding sera were measured, using the technique of indirect immunofluorescence. The results suggest that the isolates from the middle ear and ear canal are not always identical. There is some evidence that specific IgM and IgG as well as IgA responses to these organisms are present in middle ear washings and not in corresponding serum. These results suggest that coagulase negative Staphylococcus and Corynebacterium species in middle ear effusions may not be contaminants from the external canal and that a local immune response may be produced by these organisms. Whether or not these organisms represent etiologic agents responsible for otitis media with effusion cannot be ascertained from this data. One very interesting point is the presence of IgF coating of organisms in some effusions.