What organism is the causative agent of scarlet fever?

What organism 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 Streptococcus pyogenes, the Group A beta-hemolytic streptococcus. When this organism infects the throat or skin, it can release erythrogenic toxins that trigger the characteristic red, sandpaper-like rash, along with a strawberry tongue and circumoral pallor. That toxin-mediated rash is specific to this organism, which is why this answer is the best fit. The other bacteria listed are associated with different infections and do not produce the scarlet fever–causing toxin profile. In practice, treatment with penicillin or amoxicillin reduces contagiousness after about 24 hours of therapy.

Scarlet fever is caused by toxins produced by Streptococcus pyogenes, the Group A beta-hemolytic streptococcus. When this organism infects the throat or skin, it can release erythrogenic toxins that trigger the characteristic red, sandpaper-like rash, along with a strawberry tongue and circumoral pallor. That toxin-mediated rash is specific to this organism, which is why this answer is the best fit. The other bacteria listed are associated with different infections and do not produce the scarlet fever–causing toxin profile. In practice, treatment with penicillin or amoxicillin reduces contagiousness after about 24 hours of therapy.