Mycobacterium gadium Casal & Rey Calero 1974 (Tubercle, 55: 299-308, 1974) is a rapidly growing, scotochromogenic M
ycobacterium, which exists in the “Approved Lists of Bacterial Names” (Int. J. Syst. Bacteriol. 30: 225-420, 1980). It was documented that the type strain ATCC 27726 (M. Casal 1066) was differentiated from all other rapidly growing, scotochromogenic mycobacteria and was considered to belong to a distinct species (Tsukamura, M. et al.: Int. J. Syst. Bacteriol. 31: 263-275, 1981). However, since it was described on a single strain by Casal and Rey Calero, it is desired to characterize the species using more strains. We received three additional strains from Prof. M. Casal and studied on four strains, including the type strain ATCC 27726.
The characters of the type strain are shown in Table 1, and characters useful for differentiating among rapidly growing, scotochromogenic mycobacteria are shown in Table 2.
The species M. gadium together with other three,
Mycobacterium aurum,
M. thermoresistibile and
M. duvalii, are characteristic in their negative arylsulfatase activity after 14 days. Among rapidly growing, scotochromogenic mycobacteria, only these four species show a negative arylsulfatase activity after 14 days. Differentiation of
M. gadium from
M. aurum,
M. thermoresistibile and
M. duvalii is made as shown in Table 3.
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