OPSONIZATION AND PHAGOCYTOSIS OF BACTERIA DURING VARIOUS MIDDLE-EAR INFECTIONS

Samples of middle ear effusions (MEE) obtained from 50 children suffer ing from acute purulent otitis media (AOM; 23 ears), otitis media with effusion (OME; 15 ears) or chronic suppurative otitis media (COM; 23 ears) were subjected to cytological (cellular differentiation, degree of phagocytosis) and bacteriological (species quantification and ident ification, degree of opsonization) analyses. Methods used were direct microscopy of acridine orange stained material, immunofluorescence ass ay using fluorescein-labelled antibodies to immunoglobulin G (IgG) and complement cleavage product C3b, and standard bacterial culturing on agar plates. The most intense opsonization and phagocytosis was eviden t in COM effusions culture-positive for Staphylococcus aureus. AOM and OME effusions showed rather poor opsonization and roughly 1% of the p hagocytes harboured intracellular bacteria. COM effusions, culture-pos itive for Pseudomonas aeruginosa, showed no bacterial opsonization or phagocytosis whatsoever. Opsonization and phagocytosis of bacteria in the middle ear cleft is highly species-specific.