Ammonia production as a virulence expression by Mycoplasma salivarium.

Rabbits were inoculated intracutaneously with M. salivarium (ATCC 23064) cells. The size of the resulting swelling was significantly larger in 1) the sites inoculated with viable cells (7.5 x 10(9) CFU) suspended in a medium with arginine (arginine medium) than in those inoculated with killed cells, and in 2) those inoculated with cells suspended in arginine medium than with cells suspended in arginine-free medium. The swelling was enhanced when rabbits had previously been immunized with the organism. This effect was concluded to be due to ammonia which the organism produced by the hydrolysis of arginine through the arginine-dihydrolase pathway.