Figure 3.

(A, B) Bacterial distribution within wild-type (C57BL/6) cornea inoculated with GFP-expressing P. aeruginosa strain PAO1for 5 hours in vivo, as assessed using fluorescence imaging. Healthy corneas were clear of inoculated bacteria (A). Blotted corneas showed bacterial adherence to the superficial surface (arrow), but bacteria were not detected below the surface within deeper layers of the corneal epithelium (B). (C, D) Impact of ex vivo inoculation on susceptibility of the blotted cornea to P. aeruginosa penetration. The impact of excluding tear fluid was examined by comparing in vivo inoculation to inoculation of excised eyeballs in vitro. Corneas of wild-type (C57BL/6) mice were tissue paper blotted, then inoculated with GFP-expressing P. aeruginosa strain PAO1 (green) either in vivo (C) or after excision ex vivo (D) for 5 hours. In both situations, bacteria adhered to the corneal epithelium (arrows) but did not traverse. Scale bar, 10 μm. Green: bacteria (GFP); blue: cell nuclei (DAPI); red: laminin (rhodamine).