Is chronic OM a disease of microbial biofilm?

Investigators' analysis of biopsy specimens from the middle-ear mucosa of children with otitis media with effusion (OME) and recurrent OM upheld the so-called biofilm hypothesis: Namely, chronic OM is associated with the presence of biofilm (aggregated bacteria that usually adhere to a surface-in these cases, the middle-ear mucosa). The study was conducted in 26 children who were undergoing placement of a tympanostomy tube for treatment of OME and OM; controls were three children and five adults undergoing cochlear implantation.

Confocal laser scanning microscopic (CLSM) images were obtained from biopsy specimens of the middle-ear mucosa and were evaluated for biofilm morphology using generic stains and species-specific probes for Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Effusions, when present, were evaluated by polymerase chain reaction and culture for evidence of pathogen-specific nucleic acid sequences and bacterial growth.

Of the 26 children (mean age, 2.5 years) undergoing placement of a tympanostomy tube, 13 (50%) had OME, 20 (77%) had recurrent OM, and seven (27%) had both diagnoses. CLSM revealed biofilm on 46 (92%) of 50 middle-ear mucosa specimens from these children, including those that were not associated with effusion. Biofilm was not observed on any of the eight control middle-ear mucosa specimens (Hall-Stoodley L et al: JAMA 2006;296:202).