This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': 'Intact cornea can be penetrated by \nSelect and explain. \nA. Gonococcus, B. Pseudomonas, C. Streptococcus, D. Pneumococcus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A few species of bacteria are capable of penetrating an intact corneal epithelium -\n\ni. Neisseria gonorrhoea\nii. Corynebacterium diphtheriea\niii. Haemophilus agyptus\niv. Neisseria meningitidis\nv. Listeria species \xa0Bacteria which cause comeal ulcer after epithelial injuries are -\ni. Pseudomonas\nii. Pneumococcus\niii. Staphylococcus aureus\niv. Morexella\nv. Streptococcus epidermids\nvi. Enterobacterias \xa0Most common bacterial cause of keratitis;comeal ulcer →\nStaphylococcus aureus, \xa0Most common cause of keratitis/comeal ulcer in a contact lens wearer → Pseudomonas o Most common viral cause of keratitis/comeal ulcer → HSV', 'role': 'assistant'}]