What is the causative agent of scarlet fever?

What is the causative agent of scarlet fever?

• A. Group A β-hemolytic streptococci (GABHS)
• B. Staphylococcus aureus
• C. Streptococcus pneumoniae
• D. Pseudomonas aeruginosa

Answer: (A)

Scarlet fever is caused by toxins produced by Group A beta-hemolytic Streptococcus (Streptococcus pyogenes). A throat infection with this organism can release erythrogenic (pyrogenic) toxins that trigger the characteristic red, sandpaper-like rash and fever seen in scarlet fever. The underlying bacterium is the same one that causes strep throat, but the rash results from toxin production rather than the bacteria alone. This differentiates it from the other organisms listed: Staphylococcus aureus causes skin infections and toxic conditions but not the classic scarlet fever rash; Streptococcus pneumoniae leads to pneumonia and meningitis rather than scarlet fever; Pseudomonas aeruginosa is associated with opportunistic infections in certain settings and has a different clinical presentation.

Scarlet fever is caused by toxins produced by Group A beta-hemolytic Streptococcus (Streptococcus pyogenes). A throat infection with this organism can release erythrogenic (pyrogenic) toxins that trigger the characteristic red, sandpaper-like rash and fever seen in scarlet fever. The underlying bacterium is the same one that causes strep throat, but the rash results from toxin production rather than the bacteria alone. This differentiates it from the other organisms listed: Staphylococcus aureus causes skin infections and toxic conditions but not the classic scarlet fever rash; Streptococcus pneumoniae leads to pneumonia and meningitis rather than scarlet fever; Pseudomonas aeruginosa is associated with opportunistic infections in certain settings and has a different clinical presentation.