Bacteriology in acute mastoiditis.

During the period from July 1979 to December 1979, the bacteriology of 35 consecutive patients undergoing surgery for acute mastoiditis was studied. The patients' ages ranged from 3 to 13 years. All patients presented with a purulent otorrhea and a postauricular subperiosteal abscess and were subjected to a mastoidectomy within 12 hours of presentation. Specimens were obtained intraoperatively from the mastoid cavity and, using appropriate technology, were cultured for aerobic and anaerobic organisms. Bacteria were isolated from specimens of 32 patients (91.4%); specimens from three patients (8.6%) yielded no growth. Aerobes alone were cultured from four patients (11.4%); six patients' cultures (17.1%) yielded only anaerobes; and 22 patients' cultures (62.8%) had both aerobic and anaerobic organisms. Thus, anaerobes were cultured from a total of 28 patients (80.0%).