Intact cornea can be penetrated by
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
Gonococcus
Pseudomonas
Streptococcus
Pneumococcus