A 2-year survey of Branhamella catarrhalis in a general hospital

During a 2-year period, 143 strains of Branhamella catarrhalis were recovered from 7929 respiratory tract specimens (mainly sputa) sent for routine microbiological investigations at a 500 bed general hospital. The incidence of beta-lactamase positive strains increased from 2.7% in 1983 to 40% of isolates in the last 5 months of 1984; this increase continued in the early months of 1985. Forty-four strains of Bran. catarrhalis recovered from 35 patients were considered on laboratory generated data potentially pathologically significant. Almost half of the beta-lactamase producing strains were recovered from these 35 patients. Clinical information from 21 of these patients revealed the isolates in all cases to be associated with the advent of a respiratory tract infection. Appropriate antibiotic therapy in 16 of the 21 patients resulted in clinical improvement although in only 11 of these was Bran. catarrhalis specifically considered the causative pathogen. Underlying lung pathology seemed a major factor in permitting Bran. catarrhalis to express its pathogenic potential.