Highly Reproducible Techniques for Use in Systematic Bacteriology in the Genus Mycobacterium: Tests for Niacin and Catalase and for Resistance to Isoniazid, Thiophene 2-Carboxylic Acid Hydrazide, Hydroxylamine, and p-Nitrobenzoate

This is a report of the second cooperative study, conducted by the International Working Group on Mycobacterial Taxonomy, to standardize and establish reproducibility of tests for classifying and identifying mycobacteria. Five tests that met specified rigorous criteria have already been described (Wayne et al., 1974). In the present report, six additional tests are described which meet these criteria. They are tests for production of niacin and of catalase and for resistance to 10 μg of isonicotinic acid hydrazide (isoniazid) per ml, 1 μg of thiophene 2-carboxylic acid hydrazide per ml, 250 μg of hydroxylamine hydrochloride per ml, and 500 g of p-nitrobenzoate per ml.