Bacteriology of chronic otitis media

Tympanocentesis was performed in 50 patients with chronic otitis media; pus was cultured aerobically and anaerobically. Only aerobes were isolated from 21 patients (42%), three patients had only anaerobes (Peptococcus sp), and 25 patients (50%) had both aerobes and anaerobes. Only one specimen had no growth. There were 68 aerobic isolates. Pseudomonas aeruginosa was recovered in 36 patients (72%); other aerobes commonly recovered included Proteus sp and Staphylococcus aureus. There were 48 anaerobes isolated. Anaerobic Gram-positive cocci were isolated in 24 instances (21 Peptococcus sp and three Peptostreptococcus sp). Sixteen Bacteroides sp were recovered, including seven B fragilis group and six B melaninogenicus.