Topographic distribution of biofilm-producing bacteria in adenoid subsites of children with chronic or recurrent middle ear infections

Bacterial biofilms have been found in the adenoids of children with recurrent acute otitis media (AOM) and persistent otitis media with effusion (OME). However, the possible difference in biofilm-producing bacteria (BPBs) between the adenoid surface at the nasopharyngeal dome (ND) and near the ostium of the eustachian tube (ET) has not been investigated. This study aimed to assess the difference in BPBs between adenoid biopsy specimens of the ND and those taken near the pharyngeal ostium of the ET in children with chronic adenoiditis with recurrent AOM and/or persistent OME. METHODS: We collected adenoid biopsy specimens from the ND and ET during transoral endoscopic adenoidectomy to assess BPB by means of spectrophotometric analysis. RESULTS: We collected 135 adenoid biopsy specimens from 45 children. BPBs were detected significantly (p = 0.04) more frequently in the ET samples than in the ND samples, mainly Staphylococcus aureus. Although the prevalence of S aureus was slightly greater in the ND samples, and that of Streptococcus pneumoniae and Moraxella catarrhalis was slightly greater in the ET samples, these differences were not statistically significant. CONCLUSIONS: The fact that BPBs were significantly more frequently located near the ostium of the ET suggests that the adenoids are a reservoir for bacteria and indicates that hypertrophic adenoids (particularly hypertrophy near the ostium of the ET) play a role in recurrent AOM and/or OME.