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
Intact cornea can be penetrated by 
Select and explain. 
A. Gonococcus, B. Pseudomonas, C. Streptococcus, D. Pneumococcus
A: Gonococcus
Answer: A: Gonococcus 
Explanation: A few species of bacteria are capable of penetrating an intact corneal epithelium -

i. Neisseria gonorrhoea
ii. Corynebacterium diphtheriea
iii. Haemophilus agyptus
iv. Neisseria meningitidis
v. Listeria species  Bacteria which cause comeal ulcer after epithelial injuries are -
i. Pseudomonas
ii. Pneumococcus
iii. Staphylococcus aureus
iv. Morexella
v. Streptococcus epidermids
vi. Enterobacterias  Most common bacterial cause of keratitis;comeal ulcer →
Staphylococcus aureus,  Most common cause of keratitis/comeal ulcer in a contact lens wearer → Pseudomonas o Most common viral cause of keratitis/comeal ulcer → HSV