FIG 6.

Prophylaxis with vancomycin concurrent with propofol anesthesia increases kidney pathology associated with MRSA infection. (A) Mice were intravenously injected with vehicle alone, propofol alone, vehicle plus vancomycin, or propofol plus vancomycin 24 h prior to i.v. infection with 3 × 10⁶ CFU of S. aureus. Mice were sacrificed at 4 days postinfection, and kidneys were harvested, homogenized, and plated to determine viable CFU. Vancomycin treatment prior to infection decreased bacterial burdens at 4 days postinfection in control mice compared with anesthetized mice. Data are representative of 2 independent experiments. (B) Animals were infected as described for panel A and sacrificed at 4 days postinfection. Kidneys were harvested, fixed, and processed for H&E staining. Propofol treatment resulted in significantly larger areas of kidney sections affected by inflammation and necrosis (arrow, top right). Infected animals given vehicle solution and vancomycin (top left), vehicle alone (bottom left), or propofol alone (bottom right) displayed no signs of inflammation. Images were taken at ×4 magnification; scale bar, 100 μm. Data are representative of 5 animals per treatment group. (C) Area per kidney section associated with inflammation and/or necrosis. (D) Animals were infected as described for panel A, and kidneys were processed for immunofluorescent staining. Kidneys from propofol-treated animals (bottom) contained significantly greater amounts of Ly-6G⁺ inflammatory neutrophilic infiltrate (red) and S. aureus (green). Images were taken at ×20 magnification; scale bar, 50 μm. Data are representative of 2 independent experiments with 3 to 4 animals per treatment group. (E) Kidneys from propofol-treated animals contained larger areas infected with S. aureus than did control animals. *, P < 0.05.