Hordeolums are typically caused by infection with which organism?

• A. Staphylococcus
• B. Streptococcus
• C. Pseudomonas
• D. Neisseria

Answer: (A)

Hordeolums are acute infections of the eyelid margin, most often involving the glands of Zeis or Moll (external) or the meibomian glands (internal). The organism that most commonly causes these lid infections is Staphylococcus aureus, a common skin bacterium that readily colonizes the eyelid margin and gland openings, leading to a tender, red nodule with possible pus. While Streptococcus and other bacteria can occasionally be involved, they are less typical for a standard hordeolum. Pseudomonas is more associated with contact lens–related issues or corneal ulcers, and Neisseria with purulent conjunctivitis or gonococcal infections, not the usual lid stye. Thus, Staphylococcus aureus best explains the typical presentation of a hordeolum.