METABOLISM OF SILICON AS A PROBABLE PATHOGENICITY FACTOR FOR MYCOBACTERIUM AND NOCARDIA SPP

The role of silicon (Si) in metabolism and growth of 22 strains of myc obacteria and 3 strains of nocardiae, which were mostly pathogenic, wa s studied on Kirchner's medium solidified with sodium metasilicate (KS M) and the C-free solidified metasilicate minimal medium (SMM) consist ing of mineral salts only. On KSM, initial growth of mycobacteria appe ared to be better, compared with that on Lowenstein-Jensen medium (LJM ), although subsequent growth on the former was slower. On SMM lacking C, growth of mycobacteria and nocardiae could be achieved, only after repeated passages. These findings indicate that the mycobacteria and nocardiae are able to utilise Si at least to a limited extent, possibl y as an alternative to C, with greater chances of survival.