Abstract
The biochemical characteristics of 114 respiratory Haemophilus isolates were examined by the Minitek and Microbact systems. The Microbact system was easy to use and read, although some of the less important reactions (glucose and xylose) were difficult to interpret on occasions. On the basis of the 3 crucial reactions – indole production, ornithine decarboxylase and urease activity – discrepancies between the two systems were minor. Given careful standardization of techniques the Microbact system is a suitable alternative to established techniques for the biotyping of H. influenzae and H. parainfluenzae.