Purpose: To report a culture-proven, delayed-onset Cutibacterium acnes endophthalmitis following intravitreal dexamethasone implant (Ozurdex®) and to highlight diagnostic and therapeutic nuances that distinguish infectious C. acnes inflammation from sterile postimplant reactions. 

Case report: A 75-year-old pseudophakic man with proliferative diabetic retinopathy and neovascular glaucoma in the right eye presented with pain, redness, hypopyon, and vitritis seven weeks after Ozurdex. Initial management consisted of anterior chamber (AC) paracentesis and intravitreal vancomycin/ceftazidime, plus intensive topical therapy and systemic steroid taper. Because of an indolent but persistent course, a pars plana vitrectomy (PPV) was performed without IOL/capsular manipulation, combined with intravitreal vancomycin, triamcinolone, and aflibercept (for neovascular control). Prolonged incubation of the AC specimen grew C. acnes on day 11; other aerobic/fungal cultures were negative, and PCR was not performed. Inflammation resolved without relapse, and visual acuity improved to 20/30 at 18 months. A fluocinolone acetonide implant placed at 12 months for macular disease did not trigger recurrence. 

Conclusion: Delayed-onset C. acnes endophthalmitis can occur after intravitreal steroid implantation and mimic sterile inflammation. Microbiologic confirmation often requires extended anaerobic incubation (≥10–14 days), with PCR as a useful adjunct where available. In carefully selected eyes without demonstrable capsular involvement, PPVbased management with intravitreal antibiotics—without immediate capsulectomy/IOL exchange—can achieve durable cure and good visual outcomes, provided close follow-up confirms long-term quiescence.