Sialidase activity of the "Streptococcus milleri group" and other viridans group streptococci

Abstract

Viridans group streptococci were examined for the production of sialidase (neuraminidase) activity, using the fluorescent substrate 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid in a simple and rapid (15-min) assay. Sialidase was produced by all strains of Streptococcus oralis and S. intermedius and by a majority of S. mitis strains. S. mutans, S. sobrinus, S. gordonii, S. sanguis, S. vestibularis, S. salivarius, S. anginosus, S. constellatus, "S. parasanguis," and the "tufted fibril group" were uniformly negative. Sialidase production may be a useful characteristic to assist in the identification of viridans group streptococci.