Development of a test system for rapid differentiation of Neisseria and Haemophilus spp.

Abstract

A qualitative micromethod (IDS Rapid NH system) employing conventional and single-substrate enzyme tests was developed for the biochemical characterization of Neisseria spp., Haemophilus spp., and other gram-negative species. A total of over 140 dehydrated, miniaturized biochemical tests were investigated for their ability to distinguish species. Computer-assisted test selection and pair separation analysis of the data allowed the selection of 11 4-h tests that would identify Haemophilus and Neisseria spp. implicated as etiological agents as well as differentiate them from other Neisseria spp., Moraxella spp., Branhamella catarrhalis, Centers for Disease Control M groups, and Kingella spp. The final test configuration included modified glucose, sucrose, galactosidase, nitrate, phosphatase, resazurin reduction, and two arylamidase tests. In addition, indole, urea, and ornithine decarboxylase tests were included to biochemically type strains of Haemophilus influenzae and Haemophilus parainfluenzae.