Comments - Alpha hemolytic streptococci are commonly referred to collectively as the Viridans group. They colonize the respiratory tract at birth and have a low degree of pathogenicity.
Lipoteichoic acid mediates the bacterial attachment.
Specific strains include S. mutans that causes dental caries by utilizing oral sucrose to form polysaccaride glucans for attachment to tooth enamel. This organism is not found in edentulous individuals. Colonized animals maintained on monosaccharide diets have little or no tooth decay demonstrating the specific role of sucrose in decay. Other species include S. salivarius, S. bovis, S. mitis and S. sanguis. Most strains remain sensitive to penicillin.