Aerobic and anaerobic bacteriology of otorrhea associated with tympanostomy tubes in children.

The microbiology of in 55 ear aspirates obtained from 34 children with chronic otorrhea was studied. Aspiration of the middle ear exudate was done immediately following removal of tympanostomy tube (TT). The middle ear aspirates and swab specimens of the external auditory canals were cultured for aerobic and anaerobic bacteria. Sixty-five isolates were recovered only from the middle ears, 73 only from the external ear canals, and 73 were present at both sites. Analysis of the 138 middle ear isolates demonstrated the recovery of aerobic bacteria only in 28 patients (50%), anaerobes only in seven (13%), and both aerobes and anaerobes in 20 (36%). There were 77 aerobic and 61 anaerobic isolates. Commonly recovered aerobes were Pseudomonas aeruginosa (17 isolates), Staphylococcus aureus (11), Proteus sp. (7), Moraxella catarrhalis (6), Klebsiella pneumoniae (5) and non-typable Haemophilus influenzae (5). Commonly isolated anaerobes were Peptostreptococcus sp. (25 isolates), Prevotella sp. (10), Bacteroides sp. (8) and Fusobacterium sp. (6). Pseudomonas aeruginosa and S. aureus were more often isolated in children older then 6 years. These findings demonstrate the polymicrobial bacteriology of TT-related otorrhea in children. Specimens collected from the external auditory canals can be misleading. Reliable information can be obtained from the ear exudes when collected through the TT or through the open perforation after their removal.