Representative eyes showing keratitis caused by either the parent strain (A,C), the PLY-deficient isogenic mutant strain (B,D), or an uninfected control (E). At 24 hours post-infection, there was more infiltration of host PMNs in eyes infected with the parent strain (A) compared to eyes infected with the mutant strain (B). The clinical symptoms worsened by 48 hours post-infection and appeared more severe in eyes infected with the parent strain (C) than those infected with the mutant strain (D). Parent = K1263, Mutant = K1263ΔPLY. White arrows indicates corneal infiltrate. Hypopyon is indicated by the black arrow and outlined in black.