Moraxella catarrhalis bacteremia in children

M. catarrhalis commonly inhabits the upper respiratory tract and is an important cause of otitis media and sinusitis in children. It is considered relatively avirulent and not a cause of invasive disease. Only 25 cases of bacteremia in children have been reported to date in the English literature. Nine cases of M. catarrhalis bacteremia were identified at our hospital during 8 years (1988-1996). Four (44%) were seen in 1996. Age range was 11 to 32 months (mean & median: 20 months). All but one were black. Seven (78%) were boys. Five (56%) had underlying risk factors for infection including sickle cell disease (3), AIDS (1), and leukopenia due to malignancy & chemotherapy (1). Respiratory symptoms and fever were the presenting complaints in all cases. One patient also had preseptal cellulitis. All 9 patients had acute otitis media, 4/4 who had sinus films had sinusitis, and 3 had clinical and radiological evidence of pneumonia. Four (44%) patients had white blood cell count (WBC) ≥ 20,000/mm³, 4 had WBC's of 7,000/mm³ to 15,000/mm³, and 1 with malignancy had leukopenia of <100 WBC/mm³. Cerebrospinal fluid of the patient with preseptal cellulitis was normal. All M. catarrhalis isolates were beta-lactamase producers. Intravenous cefuroxime was given to 8 and ceftazidime to 1 (leukopenic) for 4-7 days, followed by oral amoxicillin/clavulanate in all patients. Total treatment was 10-14 days. All infections resolved. Our findings suggest that bacteremia due to M. catarrhalis is increasing. The possibility of M. catarrhalis bacteremia should be considered in febrile young children with upper respiratory infections and/or otitis media especially in those with underlying immune dysfunction. Because most isolates are beta-lactamase producers, treatment with antimicrobial resistant to beta-lactamase should be used.