A 66-year-old woman presents 6 weeks after uncomplicated phacoemulsification with mild ache, vision reduced to 6/36, and low-grade granulomatous uveitis. Examination reveals yellowish-white plaques within the capsular bag behind the IOL optic. What is the most likely causative organism?
- A Cutibacterium acnes ✓
- B Staphylococcus aureus
- C Pseudomonas aeruginosa
- D Streptococcus pneumoniae
Correct answer: A. Cutibacterium acnes
Explanation
Delayed chronic postoperative endophthalmitis presenting weeks to months after surgery with white plaques sequestered inside the capsular bag is characteristic of Cutibacterium acnes (formerly Propionibacterium acnes), an anaerobic gram-positive rod. It requires capsulectomy with intravitreal antibiotics or partial capsulectomy with vitrectomy for eradication. Virulent organisms such as S. aureus, Pseudomonas and Streptococcus cause fulminant early endophthalmitis, not indolent plaques.
Reference: AAO Basic and Clinical Science Course, Section 12: Retina and Vitreous, 2023-2024 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.