Branhamella catarrhalis respiratory infections

Branhamella catarrhalis is an aerobic Gram-negative diplococcus. It has been traditionally regarded as an oropharyngeal commensal and until recently was only identified as a pathogen in cases of bronchopulmonary infections. The aim of this study was to analyse the characteristics of the respiratory infections caused by B. catarrhalis and to know the antibiotic susceptibility of this microorganism. We retrospectively studied 32 lower respiratory tract infections, caused by B. catarrhalis (20 cases of bronchial infection and 12 cases of pneumonia), diagnosed between 1988-1989 in our hospital. All patients had an underlying disease; chronic obstructive pulmonary disease (COPD) and chronic heart disease being the most frequent. The aetiological diagnostic procedures were: sputum culture in 28 cases (15 in pure culture and 13 mixed), protected specimen brush (PSB) in three cases and transthoracic needle aspiration (TNA) in one case. Twenty B. catarrhalis isolates were penicillin and ampicillin-resistant, 11 in the pneumonia group and 9 in the bronchial infection group. All isolates were sensitive to amoxycillin-clavulanic acid and second generation cephalosporin. In our group four patients died. We conclude that B. catarrhalis is a not infrequent cause of respiratory infection, particularly in COPD patients, and that the high incidence of antibiotic resistance to penicillin and ampicillin should be taken into account before considering an empirical antibiotic treatment.