[Clinical study of respiratory infection due to Branhamella catarrhalis using transtracheal aspiration].

We clinically investigated 40 cases of respiratory infection due to B. catarrhalis by transtracheal aspiration (TTA). The cases consisted of acute bronchitis (13 cases), pneumonia (14 cases), and chronic lower respiratory tract infection (13 cases). The infection was monomicrobial in 17 cases and polymicrobial in 23 cases with respect to the organisms isolated from TTA. The principal organisms isolated in combination with B. catarrhalis in cases of polymicrobial infection were S. pneumoniae and H. influenzae. All of the 6 cases of death were patients with pneumonia who had malnutrition and immunological hypofunction. These results suggest that B. catarrhalis is an important pathogen in respiratory infection.