Abstract
SUMMARY: The oxidase test of Kovacs (1956) was applied to 1660 strains of various genera, of which 210 gave a positive reaction and 64 gave a delayed positive reaction. Members of the Neisseriaceae and Pseudomonadaceae were generally oxidase-positive, whereas members of the Enterobacteriaceae and, with few exceptions, Gram-positive organisms, were oxidase-negative; equivocal results were obtained in the Brucellaceae and the genus Bacillus. Kovacs test is simple and quickly performed, but very sensitive. Some taxonomic implications of the results are discussed.