Eight weeks after uneventful phacoemulsification, a 58-year-old woman has low-grade granulomatous uveitis with a 2 mm hypopyon and a white plaque on the posterior capsule. Cultures of aqueous are initially sterile. The most likely organism is:
- A Propionibacterium acnes ✓
- B Staphylococcus epidermidis
- C Aspergillus fumigatus
- D Pseudomonas aeruginosa
Correct answer: A. Propionibacterium acnes
Explanation
Propionibacterium acnes causes delayed chronic postoperative endophthalmitis, typically weeks to months after surgery, with indolent granulomatous uveitis, small hypopyon, and a characteristic white intracapsular plaque of organisms sequestered within residual lens matter. Cultures may need prolonged incubation. S. epidermidis causes acute postoperative endophthalmitis within days, and fungal endophthalmitis follows a more fulminant vitritis course.
Reference: AAO Basic and Clinical Science Course, Intraocular Inflammation and Uveitis Section 9, 2023-2024 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.