[Macrophage respiratory burst-inducing activity of Mycobacterium fortuitum: relationship with its virulence to mice]

Mycobacterium fortuitum strains F-3 and 126 were studied for their virulence to mice, by being given intravenously to BALB/c strain mice, in terms of incidence of spinning disease, degree of gross renal lesions and growth of organisms in kidneys. In three experiments separately carried out, strain 126 showed considerably higher virulence than strain F-3. In particular, in experiment 2, much higher incidence of spinning disease was seen in strain 126- infected mice than in strain F-3-infected ones. In experiment 3, the degree of gross renal lesions was significantly higher (P less than 0.025, chi 2-test) in the strain 126-infected animals than in the F-3-infected ones. Moreover, in experiment 2, the number of viable units in kidneys was significantly larger in the case of strain 126-induced infection than in the case of strain F-3-induced one (P less than 0.01, Student's t-test). Secondly the two M. fortuitum strains were studied for their activity to trigger chemiluminescence (a parameter for respiratory burst) of murine peritoneal macrophages, due to their contact with macrophages. In two of four experiments separately performed, strain 126 exhibited much lower activity of macrophage chemiluminescence-triggering than strain F-3. In the remaining two experiments, the triggering activities of the two strains were at almost the same level, although the activity of strain 126 was still somewhat lower than that of strain F-3.(ABSTRACT TRUNCATED AT 250 WORDS)