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Chronic Otitis Media Is Biofilm-Related

And that may explain why antibiotics lack efficacy

Chronic otitis media consists of both otitis media with effusion and recurrent otitis media. The latter is marked by resolution of clinical evidence of infection and middle-ear effusion between episodes. Bacteria are cultured from only one quarter of patients who have otitis media with effusion. Prompted by a demonstration of the formation of biofilms (aggregated bacteria attached to a surface and surrounded by an extracellular matrix) in an animal model of otitis media with effusion, these authors assessed whether chronic otitis media in humans is biofilm-related.

Middle-ear mucosa specimens from 26 children (mean age, 2.5 years; age range, 0.5–14 years) undergoing tympanostomy tube placement for chronic otitis media were compared with specimens from 3 uninfected children and 5 uninfected adults undergoing cochlear implantation. Of the 26 children with otitis, 13 (50%) had otitis media with effusion, 20 (77%) had recurrent otitis media, and 7 (27%) had both. Twenty-seven ears (52%) had effusions. Only 5 of the 27 effusions (19%) were culture-positive for any of the three major otitis media pathogens (Haemophilus influenza, Streptococcus pneumoniae, Moraxella catarrhalis), whereas all 24 effusions tested by polymerase chain reaction (PCR) were positive for at least one of these pathogens. Mucosal biofilms were identified by confocal laser scanning microscopy on 46 of 50 specimens (92%) from children with otitis and on none of the control specimens.

Comment: Otitis media with effusion can lead to conductive hearing loss and impaired speech and socialization skills. This disease has been hypothesized to be a nonbacterial inflammatory process because cultures are usually negative. However, this study’s findings suggest that the disease process is chronic with acute exacerbations and is related to the presence of biofilms containing one or more organisms. That the biofilm is a physical barrier helps explain the ineffectiveness of antibiotics and host defenses against the infection. The authors do not suggest changing management at this time. Clearly, methods are needed to prevent the development of the biofilm or to destroy it.

— John A. Marx, MD, FAAEM, FACEP

Published in Journal Watch Emergency Medicine August 18, 2006

Citation(s):

Hall-Stoodley L et al. Direct detection of bacterial biofilms on the middle-ear mucosa of children with chronic otitis media. JAMA 2006 Jul 12; 296:202-11.

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