Which organism is commonly linked to canaliculitis with sulfur granules?

• A. Moraxella
• B. Pseudomonas aeruginosa
• C. Treponema pallidum
• D. Actinomyces

Answer: (D)

Sulfur granules in canaliculitis point to Actinomyces israelii. This organism is a gram-positive, anaerobic, filamentous bacterium that often resides in the mouth but can chronically infect the lacrimal drainage system. The infection yields yellowish sulfur-like granules composed of densely packed filamentous colonies mixed with inflammatory debris, which can be expressed from the canaliculus. Clinically, canaliculitis from Actinomyces tends to be a slow, persistent process, and management involves removing the concretions and a prolonged course of antibiotics such as penicillin.

The other organisms listed don’t typically produce these sulfur granules in canaliculitis. Moraxella lacunata is more linked to angular conjunctivitis, Pseudomonas aeruginosa to keratitis or acute conjunctivitis, and Treponema pallidum to syphilis. The presence of sulfur granules is the classic clue that points toward Actinomyces in this scenario.