Definition: those that produce active hemolysins (O and S) that cause a zone of clear hemolysis on the blood agar medium in the area of the colony; ß-hemolytic streptococci are divided into groups (A–O) on the basis of cell wall C carbohydrate (see Lancefield classification); Group A (in the strains pathogenic in humans) comprises more than 50 types (designated by Arabic numerals) determined by cell wall M protein, which seems to be associated closely with virulence and is produced chiefly by strains with matt or mucoid colonies, in contrast to nonvirulent, glossy colony-producing strains; other surface protein antigens such as R and T (substance T), and the nucleoprotein fraction (substance P) seem to be of less importance. The more than 20 extracellular substances elaborated by strains of ß-hemolytic streptococci include erythrogenic toxin (elaborated only by lysogenic strains), deoxyribonuclease (streptodornase), hemolysins (streptolysins O and S), hyaluronidase, and streptokinase.
Synonym(s): hemolytic streptococci
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.
Search Stedman's Medical Dictionary
Examples: glitazone, GI cocktail, etc.