Skip to Content

The originating document has been archived. We cannot confirm the completeness, accuracy and currency of the content.

β-hemolytic streptococci

 

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; β-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 β-hemolytic streptococci include erythrogenic toxin (elaborated only by lysogenic strains), deoxyribonuclease (streptodornase), hemolysins (streptolysins O and S), hyaluronidase, and streptokinase.

Synonym(s): hemolytic streptococci

Disclaimer: This site is designed to offer information for general educational purposes only. The health information furnished on this site and the interactive responses are not intended to be professional advice and are not intended to replace personal consultation with a qualified physician, pharmacist, or other healthcare professional. You must always seek the advice of a professional for questions related to a disease, disease symptoms, and appropriate therapeutic treatments.
© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.
Hide