Antibiotic efficacy in intraabdominal sepsis: a clinically relevant model

We present preliminary data on the role of antibiotics in intraabdominal sepsis using a new, clinically relevant animal model. Peritoneal cavity infection was induced by ligation and perforation of the cecum in adult rats. Surviving rats were randomized to receive either saline or cefoxitin at the time of cecal excision and peritoneal lavage, 18 h after the onset of infection. This is different from previous models of abdominal sepsis (in which antibiotics are given within 4 h of peritoneal contamination) and mimics the clinical setting in which antibiotics are initiated much later, at the time of operation. Antibiotic-treated rats received 20 mg cefoxitin i.m. every 8 h for 7 days; controls received saline at similar times. Thirty-nine of 67 control rats died (58%) versus 20 of 64 (31%) that received cefoxitin (p less than 0.005). We conclude that even with delayed administration, antibiotics appear to improve the outcome of intraabdominal sepsis. With further characterization of this model we plan to use it as an in vivo assay to compare the efficacy of different antimicrobial agents in intraabdominal sepsis.