The most common etiologic agent in keratitis associated with contaminated contact lens cleaning solutions is which organism?

• A. Chiyseobacterium meningosepticum
• B. Pseudomonas aeruginosa
• C. Francisella tularensis
• D. Escherichia coli

Answer: (B)

Pseudomonas aeruginosa is the most common bacterial cause of keratitis linked to contaminated contact lens cleaning solutions because it thrives in moist, nutrient-rich environments and readily colonizes contact lens cases and solutions. Its ability to form biofilms on lens surfaces and resist disinfectants makes it a frequent culprit when solutions become contaminated, leading to rapid, aggressive corneal infection characterized by severe pain and purulent discharge. While other organisms can occasionally be involved—such as Chryseobacterium meningosepticum in some outbreaks—the likelihood is highest for Pseudomonas aeruginosa in this setting. Escherichia coli and Francisella tularensis are not typical causes of contact lens solution–associated keratitis.