Anaerobic bacteria in chronic otitis media.

The bacteriology of 70 consecutive cases of active chronic otitis media was studied. Using appropriate technology, anaerobic bacteria were recovered in 33%, Bacteroides species accounting for one half of them. They were always found in mixed infections involving the average of 3.8 bacteria, 1.9 anaerobic, and 1.9 facultative species. The bacteriology was relatively stable from one ear to the other in the ten bilateral cases studied. The results were alike in the groups differing with respect to local antimicrobial therapy or appearance of the middle ear discharge. The cases with chronic otitis in spite of previous radical surgery presented more often with anaerobic infection than the unoperated ones, and none of them yielded sterile cultures. The recognition of anerobic middle ear infections may be clinically significant because the susceptibilities of the organisms to antimicrobial agents and to air are characteristically different from those of aerobic or facultative bacteria.