A contact lens wearer develops a rapidly progressing corneal ulcer with marked stromal melting within 24 hours. Which property of the responsible organism explains this extensive tissue destruction?

• A Secretion of neuraminidase damaging epithelium
• B Intracellular survival within macrophages
• C Deposition of immune complexes in the stroma
• D Production of elastase and alkaline protease ✓

Explanation

Pseudomonas aeruginosa elaborates proteases, particularly elastase and alkaline protease, that digest collagen and glycosaminoglycans of the corneal stroma, producing the characteristic rapid suppurative melt. Immune complex deposition is the mechanism of marginal infiltrates, not of fulminant bacterial keratitis.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.