[Biochemical characterization of haemophilus-strains by using the API 20 E- and API 50e-testsystem (author's transl)]

The commercially available test systems API 20E and API 50E were used to characterize 74 reference strains and clinical isolates of Haemophilus influenzae, H. aegyptius, H. parainfluenza, H. paraphrophilus and H. paraphrohaemolyticus The strains were grown on chocolate agar followed by suspending some colonies colonies in proteose pepton medium, pH 7.6, supplemented with the X- and V-factors. The alkaline suspension was used to inoculate the cups of the test kits. The alkali of the medium did not influence the biochemical reactions of the bacteria and enabled elimination of false positive reactions, particularly with the indicator phenol red. The API-systems proved efficacious for the diagnosis and characterization of the strains as compared with conventional biochemical tests.