A 70-year-old patient presents 5 days after uncomplicated phacoemulsification with acute painful red eye, hypopyon, and vitreous haze. The most feared causative organism associated with an acute post-operative endophthalmitis within the first week is:

• A Staphylococcus epidermidis ✓
• B Staphylococcus aureus
• C Propionibacterium (Cutibacterium) acnes
• D Candida albicans

Explanation

Staphylococcus epidermidis (coagulase-negative staphylococcus) is the most common organism causing acute post-operative endophthalmitis after cataract surgery, accounting for approximately 50–70% of cases. S. aureus, Streptococcus, and gram-negative organisms cause more virulent acute presentations. Cutibacterium (formerly Propionibacterium) acnes causes a characteristic delayed, chronic post-operative endophthalmitis occurring 4 weeks to several months after surgery, with white plaques in the capsular bag. Candida causes endogenous endophthalmitis in immunocompromised patients or those with prolonged IV catheterization.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.