Isolation of Branhamella catarrhalis from sputum and clinical features of bronchopulmonary infection due to Branhamella catarrhalis

The authors investigated the isolation of Branhamella catarrhalis from sputum and the clinical features of bronchopulmonary infection due to B. catarrhalis from January of 1983 to December of 1987 at the Hokusyo Central Hospital. B. catarrhalis was cultured from 106 (3.8%) of 5,674 sputum specimens. The isolation rate did not vary during the 5 years from 1983 to 1987. Approximately 70% of the patients had some underlying bronchopulmonary disease. The strains of beta-lactamase-positive B. catarrhalis have increased recently in our hospital. Using 4 diagnostic criteria for bronchopulmonary infection by B. catarrhalis, 24 cases were detected. MIC was measured in 97 strains of B. catarrhalis (beta-lactamase positive 63 strains, negative 34 strains). beta-lactamase positive strains had a high MIC value for beta-lactam antibiotics, but antibiotics including beta-lactamase inhibitor markedly improved sensitivity to drugs. Negative strains showed good sensitivity to beta-lactam antibiotics. Cases of bronchopulmonary infection due to Branhamella catarrhalis and beta-lactamase-productive strains are increasing, therefore it is necessary to be careful in the choice of antibiotics.