The " Dassie " Bacillus.
AbstractThis mycobacterium was originally isolated from an epithelioid granuloma in the lungs of the rodent common to South Africa, Procavia capensis or " Dassie", by WAGNER et al. (Nature, 1958, v. 181, 284). The organism appeared to resemble the vole bacillus but although it produced caseation of lymph glands when injected into other Dassies, it was of very low virulence to rabbits, guineapigs, mice and various other veldt rodents.
The present author has examined the strain and finds that morphologically it resembles the vole bacillus by being very pleomorphic in lesions and the curved forms tending to form spirals or hooks, but differing by being more granular. It is strongly acid-fast.
Culturally it was a strict aerobe that takes 6 weeks for the primary growth to develop on Dorset egg medium, but it grew more rapidly in secondary cultures; on this medium the growth was almost white, rough and friable. It could be readily adapted to grow in Dubos medium, and experiments with the basal medium showed that 0-1% sodium glutamate with 0-2% asparagine was preferable to casein digest as the source of nitrogen.
The bacillus was slightly more sensitive to streptomycin and isoniazid than is H37Rv, and it survived exposure to 10% NaOH and H2SO4 for 30 minutes and to 0-5% phenol for 24 hours; it was killed by heating for 30 minutes at 60 °C. but not at 55 °C. S. R. M. Bushby.