Evaluation of Bacto TB hydrolysis reagent (Tween 80) for the identification of Branhamella catarrhalis.

An investigation of the hydrolysis of Tween 80 reagent by Branhamella catarrhalis and related organisms (Neisseria and Moraxella species) revealed that only B. catarrhalis gave a positive result. A total of 226 strains, including reference organisms and clinical isolates, were studied. B. catarrhalis changed the color of the reagent from amber to pink-red after overnight incubation. We recommend this simple and cost-effective test as an alternative procedure to DNase testing or tributyrin hydrolysis or as a supplemental procedure for the identification of B. catarrhalis in clinical specimens.