Branhamella catarrhalis bronchopulmonary isolates in PICU patients

Branhamella catarrhalis is commonly considered a respiratory commensal but has recently been implicated as a pathogen, particularly in adults. Over a 28 month period, B. catarrhalis was isolated from bronchopulmonary secretions of 14 PICU patients with acute respiratory infections. Twelve patients had pneumonia and two had tracheitis. The mean age was 3.5 years. Seven patients had chronic cardiopulmonary disease including two who were immunosuppressed. Three had an acute underlying condition and four had no complicating medical problem. Polymorphs and Gram-negative diplococci on Gram stain were found in respiratory secretions of all patients. Twelve of 14 isolates produced beta-lactamase, and six patients had a second potentially pathogenic bronchopulmonary isolate. All patients were treated for B. catarrhalis infection and none died. When isolated in pure culture from bronchopulmonary secretions in symptomatic patients, B. catarrhalis should be considered a pathogen. When isolated in mixed culture, its pathogenic role is uncertain. We conclude that B. catarrhalis can be a bronchopulmonary pathogen in critically ill children with otherwise normal cardiopulmonary function as well as in those with chronic cardiopulmonary dysfunction. When administering antibiotics the high frequency of beta-lactamase-producing strains must be taken into consideration.