The microbiology of chronic otitis media with effusion in a group of Auckland children

Aims. To determine the microbiology of chronic otitis media with effusion in a group of Auckland children. To determine the antimicrobial sensitivities of isolated bacterial pathogens to commonly used antibiotics for this condition. Methods. A descriptive study recruiting subjects from otherwise well children with chronic otitis media with effusion having insertion of ventilation tubes at Starship Children's Health, Auckland. Tympanocentesis was performed, the middle ear aspirate cultured and antimicrobial sensitivities obtained. Results. Sixty seven children (11 mo to 8 yr) with chronic otitis media with effusion had tympanocentesis of 105 ears. 38/105 (36%) of the middle ear aspirate cultures were positive. Forty nine organisms were isolated with 10 ears having two or more different bacteria identified. Isolated were 17 Haemophilus influenzae (16 nontype b and 1 type b), 13 Moraxella catarrhalis, nine Streptococcus pnuemoniae and 10 'others'. All S pneumoniae(9/9), most H influenzae(14/17) and no M catarrhalis(0/13) were sensitive to amoxycillin. More than 80% of subjects had either a sterile effusion or an organism sensitive to amoxycillin or cotrimoxazole. Conclusions. Middle ear effusions were culture positive in a third of cases of chronic otitis media with effusion. The commonest organisms were H influenzae nontype b, M catarrhalis and S pnuemoniae. This is similar to reports from other countries. Sensitivity data obtained supports the continued recommendation of amoxycillin or cotrimoxazole as first line therapy for the antimicrobial treatment of this condition.