[Decarboxylase activity study of Pasteurella multocida].

Ornithine-, lysine- and arginine-decarboxylase activity of 218 P. multocida strains, isolated from birds of varying disease symptoms in Bulgaria and CSSR, and from pigs, rabbits and birds in Cuba, USSR and CSSR, was studied after the method of Moller. Positive ornithine decarboxylase activity was established in 211 strains, low -- in 2, and negative -- in 5 strains. Low arginine decarboxylase activity was observed in 12 Pasteurella strains, while in 14 -- low lysine decarboxylase activity. The presence of ornithine decarboxylase activity can be used, along with the cultural and biochemical properties and with lyzation by a specific bacteriophage, as a taxonomic character for the species. All Pasteurella strains pathogenic for white mice, produce ornithine-decarboxylase. Lines of the strain X 73 obtained following gamma-irradiation having lost their ornithine-decarboxylase are pathogenic for white mice.