Trimethylsilyl-sugar profiles of Streptococcus milleri and Streptococcus mitis

Seventy strains of 'viridans-group' streptococci were analysed gas chromatographically after preparation of trimethylsilyl ethers of their cellular sugars. The resulting profiles were evaluated as a possible aid to taxonomy. Glycerol, glucose, galactose, N-acetyl-glucosamine and N-acetylmuramic acid were found in all strains, in varying amounts. Rhamnose was the major neutral sugar in most strains, other than representatives of Streptococcus mitis, which invariably had ribose and usually anhydroribitol but no rhamnose. One strain of Strep. mitis possessed arabitol. Some strains of Strep. mitis and 'Strep. milleri' were alone in containing N-acetylgalactosamine. A combination of N-acetylgalactosamine and rhamnose in the absence of ribose was diagnostic for strains of 'Strep. milleri'.