Traditional biochemical identifications included a wide array of "tube" tests based on reactions. Many sources for these traditional reactions are available; the Manual of Clinical Microbiology (published by the American Society for Microbiology [ASM]) is always useful, containing charts and tables; the ability to narrow down to some of the more common and more pathogenic isolates can still be helpful today.
The premise of these keys and tables was to identify "some" gram-positive aerobic rods starting with whether the isolates fermented sugars or oxidized sugars. Gram-positive fermenters and oxidizers were divided further into groups based on catalase, nitrate, and urea reactions. The possible organisms could further be verified by reviewing an in-depth chart with the biochemical reactions. In addition, these sources also provided a key to help in identifying Bacillus species.
