Clinical and microbiological features of Branhamella catarrhalis bronchopulmonary infections.

Branhamella catarrhalis bronchopulmonary infection was diagnosed in 101 patients with clinical lower respiratory tract infections by the presence of gram-negative intracellular diplococci in sputum and growth of more than 20 colonies of B catarrhalis in quantitative culture at a 10(-7) dilution. 94 patients had either chronic chest disease or were current or previous smokers, 59 had a cause of generalised immunosuppression, and 17 had a high risk of aspiration from the oropharynx. The pathogenicity of B catarrhalis was evident from purulence of sputum, fever, blood leucocytosis, and patchy pulmonary shadowing on chest radiographs. B catarrhalis infection contributed to 4 of 6 deaths. B catarrhalis was the only bacterial pathogen isolated from the sputum of 71 patients and it was isolated with other recognised bacterial pathogens from 30 patients. All 10 isolates of B catarrhalis tested were sensitive to oxytetracycline, all 82 tested were sensitive to cefuroxime, 93 of 96 were sensitive to erythromycin, and 85 of 95 to cotrimoxazole. Beta-lactamase was produced by 38 of 99 isolates of B catarrhalis.