1009 THE BACTERIOLOGY AND CYTOLOGY OF CHRONIC MIDDLE EAR EFFUSION

Abstract

Middle ear effusions often persist in children with serous and mucoid otitis media despite medical therapy. Residual bacterial colonization of effusion may contribute to the pathogenesis of these conditions and was investigated by examining middle ear effusion for bacteria by culture and gram stain, and for cellularity by Papanicolaou stain. Effusion was obtained at the time of myringotomy and tympanostomy tube insertion from 509 ears of 317 children age 1 to 11 years; 362 effusions were mucoid, 79 were serous, and 60 were purulent. Mucoid otitis media was found most frequently in younger children, while serous otitis media predominated in older children. Bacteria were cultured from 30% of ears and included H. influenzae (15%), S. epidermidis (6%), N. catarrhalis (6%), S. pneumoniae (4%) and others (3%). An equal percentage of mucoid, serous and purulent effusions yielded bacteria by culture or gram stain. Bacteria were observed by gram stain in 16% of the sterile effusions, and the majority of the organisms were gram positive cocci. Phagocytes were noted on Papanicolaou stained smears in 37% of culture positive effusions, but were less frequent (23%) in sterile effusions. These results suggest that bacteria which are known pathogens in acute otitis media, persist in many chronic serous, mucoid and purulent middle ear effusions. The presence of bacteria as well as phagocytes in these effusions indicates chronic inflammatory stimulation which may contribute to the pathogenesis of chronic otitis media with effusion.