Branhamella catarrhalis. New methods of bacterial diagnosis

A total of 176 strains identified as Branhamella catarrhalis were isolated from various clinical specimens, mainly sputum (71), pharynx (49), eye (24), nose (11), ear (6) and tracheal aspirate (7). B. catarrhalis appeared as Gram-negative cocci in white colonies which were oxidase- and catalase-positive and which did not produce acidification of sugars. The 3 related species, Neisseria caviae, N. ovis and N. cuniculi were also white but the 'true asaccharolytic Neisseria' studied presented a yellow pigment. Only a few strains of B. catarrhalis were able to grow on selective medium. However, when Catlin's chemically defined medium was used, all strains of B. catarrhalis had a unique requirement for arginine. This characteristic differentiated B. catarrhalis from N. caviae and N. ovis (non-requiring), N. cuniculi (required cystine, proline and arginine) and N. canis and N. elongata (both non-requiring). All strains of B. catarrhalis reduced nitrate and nitrite, possessed deoxyribonuclease activity and hydrolysed tributyrin to butyric acid. B. catarrhalis liberated high concentrations of butyric acid, N. caviae, N. ovis and N. cuniculi moderate concentrations and other species of Neisseria minimal concentrations. All strains of B. catarrhalis were resistant to acetazolamide and the absence of gamma-glutamyl transferase activity differentiated B. catarrhalis from atypical meningococci which were always positive.