FIG. 7.

Phase-contrast microscopy showing tear fluid effects on P. aeruginosa morphology. Cytotoxic and invasive P. aeruginosa isolates were examined in MEM (upper panels) and compared with those exposed to tear fluid for 3 h (lower panels). Typical results for three P. aeruginosa isolates are shown. Tear fluid induced short (e.g., strain 6294) and long (e.g., strain 6206) chain formation or aggregated bacteria into clumps (e.g., strain 6073). All previously motile strains became nonmotile in tear fluid.