Which bacterium causes scarlet fever by producing toxins during some Streptococcus pyogenes infections?

Streptococcus pyogenes causes scarlet fever by producing toxins during some infections.

This Gram-positive bacterium is commonly called group A Streptococcus, or group A strep. It frequently causes strep throat and skin infections. When toxin-producing strains infect the throat or skin, they can trigger the fine, rough-textured rash associated with scarlet fever. The rash is a consequence of bacterial toxins and the host response, not a separate microorganism.

Streptococcus pyogenes can also cause cellulitis, erysipelas, and invasive infections. Streptococcus pneumoniae is another important human pathogen, but it belongs to a different species and is associated especially with pneumonia, meningitis, and ear infections. Staphylococcus aureus is likewise distinct and does not cause classic scarlet fever.