A 30-year-old woman, who frequently has her hands immersed in water due to her occupation as a cleaner, develops chronic inflammation and swelling of the nail folds of several fingers, with occasional pus discharge. The nail plates show dystrophy and discoloration. Which of the following is the most likely causative organism?

Explanation

This clinical picture describes chronic paronychia, which is frequently associated with prolonged water exposure and often caused by *Candida albicans*. The constant moisture leads to maceration of the nail fold, allowing *Candida* to colonize and cause inflammation, swelling, and occasional discharge. *Staphylococcus aureus* typically causes acute paronychia, which is more sudden onset, painful, and often purulent. *Pseudomonas aeruginosa* can cause green discoloration of the nail (chloronychia) but is less commonly the primary cause of chronic paronychia with significant nail fold inflammation. Dermatophytes cause onychomycosis, which primarily affects the nail plate itself, though they can sometimes involve the nail fold, but chronic paronychia with pus discharge is more characteristic of *Candida*.