ABO Ophthalmology Complete Practice Exam 2025

The correct answer highlights the most prevalent organisms that cause bacterial keratitis, which is an inflammation of the cornea often resulting from infection. Pseudomonas aeruginosa is a particularly notorious pathogen associated with rapid and serious corneal infections, especially in contact lens wearers. Staphylococcus species, including Staphylococcus aureus, are also common culprits, known for causing a range of ocular infections.

This combination of Pseudomonas and Staphylococcus reflects the typical microorganisms isolated in clinical cases of bacterial keratitis. Due to their virulence factors and the ability to invade tissue, these bacteria can lead to significant corneal damage if not promptly diagnosed and treated.

Other options mention organisms that, while significant in various infections, are not the primary causative agents of bacterial keratitis. For instance, Escherichia coli and Streptococcus pneumoniae, while they can cause ocular infections, are less commonly associated specifically with keratitis compared to the aforementioned organisms. Similarly, Chlamydia and Neisseria, though important in certain ocular diseases, do not represent the typical profile of bacteria seen in bacterial keratitis. Finally, Haemophilus influenzae and Candida reflect a broader range of infectious organisms but are not the key players