1. Dr Sabrina Moyo Department of microbiology and immunology

3. - S. pneumoniae - encapsulated gram-positive cocci, oval or spherical: - 0.5 - 1.2 µm diameter. - Lancet shaped, in pair or singles. - Pneumococci are very sensitive to the product of their fermentative metabolism, which result in Gram-negative reaction in older cultures. - Capsule readily demonstrated using India ink or use of homologous type-specific antibody in the Quellung reaction. - Smooth to rough variation (transformation) occurs in culture in presence of homologous antisera.