Bacterial examination of serous otitis media and experimental tubal stenosis

Involvement of bacteria in serous otitis media was studied in man and by animal experimentation (using rabbits). Bacteria from the middle ear fluid, the skin of the external ear canal and the epipharynx of 100 human ears were cultured. Bacteria were also cultured from 50 ears of rabbits with serous otitis media induced experimentally by tubal stenosis, in the same way as those taken from human ears. Bacteria were detected in the middle ear fluid of 61 human ears (61%), and in 48 human ears (48%) except for those with contamination. The bacteria detected in the middle ear fluid were the same as those detected in the epipharynx in 40 of the 50 rabbit ears during the period from the start of treatment to the 30th day. In ears which were treated for more than 30 days, the bacteria detected in the middle ear fluid tended not to be the same as those detected in the epipharynx. From these results it was inferred that inflammation of the epipharynx spread over the middle ear cavity through the auditory tube.