The genus Streptococcus is comprised of a wide variety of both pathogenic and non-pathogenic (commensal) gram-positive bacteria which are found to inhabit a wide range of hosts, including humans, horses, pigs and cows.

Is Streptococcus a pathogen?

Group A streptococci are extracellular bacterial pathogens which produce a variety of pyogenic infections involving the mucous membranes, tonsils, skin, and deeper tissues, including pharyngitis, impetigo/pyoderma, erysipelas, cellulitis, necrotizing fasciitis, toxic streptococcal syndrome, scarlet fever, septicemia, ...

Which type of Streptococcus is most commonly pathogenic?

Diseases Caused by Streptococci. The most significant streptococcal pathogen is S. pyogenes, which is beta-hemolytic and in Lancefield group A and is thus denoted as group A beta-hemolytic streptococci (GABHS). ) sometimes occur ≥ 2 weeks after infection.