Amphotericin B-induced resistance to Pseudomonas aeruginosa infection in mice

We evaluated the effects of amphotericin B (AmB) against Pseudomonas aeruginosa (P. aeruginosa) infection in mice. Pretreatment with 2 mg/kg of AmB 24 hours before infection significantly increased the survival rates of mice intraperitoneally infected with either P. aeruginosa or Escherichia coli. To evaluate the mechanism of this AmB-induced resistance to infection, we conducted a number of experiments. Peritoneal macrophages exposed in vitro to AmB showed superior bactericidal activity compared to that of control macrophages. Interleukin-1 production by peritoneal macrophages from mice pretreated with 2 mg/kg of AmB was significantly higher than that in control mice. Serum tumor necrosis factor level after intravenous injection of P. aeruginosa was also higher in mice pretreated with 2 mg/kg of AmB than in control mice. These data indicate that AmB induces resistance to P. aeruginosa in mice. Furthermore AmB-induced activation of peritoneal macrophages and their production of interleukin-1 and tumor necrosis factor appeared to play important roles in this phenomenon.