A farmer sustains a soil-contaminated corneal laceration from a tree branch. Twenty-four hours later he presents with violent pain, marked lid oedema, hypopyon, and rapid progression to panophthalmitis. Vitreous biopsy shows large gram-positive rods with plate-like colonies. The causative organism is:

• A Pseudomonas aeruginosa
• B Clostridium perfringens
• C Bacillus cereus ✓
• D Nocardia asteroides

Explanation

Bacillus cereus is the classic cause of fulminant post-traumatic endophthalmitis after soil-contaminated open globe injuries. It is a gram-positive rod producing exotoxins that destroy intraocular tissues within 24 to 48 hours, often progressing to panophthalmitis despite treatment. Pseudomonas is gram-negative, Clostridium causes gas gangrene of soft tissue rather than typical intraocular infection, and Nocardia is a weakly acid-fast filamentous organism with a subacute course.

Reference: Yanoff and Duker Ophthalmology, 5th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.