A gram-positive rod sometimes associated with pharyngitis is which organism?

• A. Arcanobacterium haemolyticum
• B. Bacillus cereus
• C. Corynebacterium urealyticum
• D. Erysipelothrix rhusiopathiae

Answer: (A)

When you see a gram-positive rod in a patient with pharyngitis, Arcanobacterium haemolyticum fits best. It’s a non-spore-forming, gram-positive rod that has long been associated with exudative throat infections, especially in adolescents and young adults. On culture, it can exhibit beta-hemolysis on blood agar and may be mistaken for streptococcal infection, which is a clue that helps connect the organism to this clinical picture.

The other organisms listed don’t typically present with pharyngitis: Bacillus cereus is mainly linked to food poisoning and is a spore-former; Erysipelothrix rhusiopathiae causes erysipeloid skin infections after animal or fish exposure; Corynebacterium urealyticum is more often implicated in urinary tract infections and is not a throat pathogen.