[Research technics of enzymes used in the diagnosis of gram negative bacteria (author's transl)].

The enzymes used in the identification of Gram negative bacteria belonging to the families of Enterobacteriaceae, Vibrionaceae, Parvobacteriaceae, Pseudomonadaceae and to the genera Alteromonas, Xanthomonas, Alkaligenes, Flavobacterium are classified arbitrarily by the author into enzymes essential for the diagnosis of the family (oxidase, nitratase), enzymes useful in the diagnosis of the genus or the species (ONPG-hydrolase, urease, oxidative desaminase, lysine decarboxylase and ornithine, arginine dihydrolase, thiosulphate reductase, pectinase), and into enzymes sought to confirm the diagnosis (tetrathionate reductase, gelatinase, lipase, DNase, amylase, beta-xylosidase, lecithinase). The technics permitting their identification are described and their distribution in the species and genera studied is reported.