The clinical role of Alloiococcus otitidis in otitis media with effusion.

OBJECTIVE: To investigate the presence of Alloiococcus otitidis (A. otitidis) in MEEs from patients with otitis media with effusion (OME) using PCR and to correlate the findings with the clinical picture of children with OME for assessing the clinical role of A. otitidis in OME.

METHODS: Bacterial culture and PCR were used to detect A. otitidis, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in MEE samples from 123 patients with OME. The culture and PCR results and the clinical picture of the patients were compared.

RESULTS: Bacteria were cultured in 55 (45%) of the 123 MEEs, and major pathogens (S. pneumoniae, H. influenzae and M. catarrhalis) were found in 40 (33%); A. otitidis was not found in culture. PCR of the MEEs yielded positive results for one or more of the four tested pathogens in 108 (88%) of the samples and 25 (20%) were positive for A. otitidis. The effusions that persisted 3 months or longer had a higher prevalence of A. otitidis than those with shorter durations (P=0.03). A. otitidis was found to be more often positive in PCR in mucoid MEEs than in mucoserous MEEs (30 vs. 9%; P=0.015).

CONCLUSIONS: While A. otitidis is extremely difficult to detect with bacterial culture, PCR provides a sensitive and specific means for detecting it. A. otitidis is associated with a more prolonged course and mucoid MEEs in OME. Thus, its existence seems to be related to a more chronic stage of OME, but its pathogenic potential should be the subject of further investigation.