Risk of endotoxemia during the initial phase of gut decontamination with antimicrobial agents

Decontamination of the digestive tract with antimicrobial agents has been u sed for prevention and therapy of bacterial translocation. With regard to t he well-described endotoxin-releasing properties of these agents, the quest ion arises as to whether their enteral administration might result in an in creased amount of intestinal endotoxins entering the circulation. Immunocom promised Wistar rats were intraduodenally challenged with live E. coli. Con trol animals received saline solution, decontaminated rats were treated wit h either tobramycin plus polymyxin B or ciprofloxacin alone through the duo denal tube. Plasma endotoxin activity and blood bacteria count were measure d hourly over an observation period of 5 h. The intestinal bacterial count was determined at the end of the experiment. Gut decontamination in both gr oups receiving antimicrobial agents resulted in elevated plasma endotoxin l evels compared with nondecontaminated controls. Maximum endotoxin levels we re found to be 5-6 times higher in the ciprofloxacin group than in the cont rol group and 2 times higher than in the tobramycin/polymyxin group. No pos itive blood cultures were detected. Intestinal bacterial count was similar in both treatment groups. Enterally applied antimicrobial agents bear an el evated risk of endotoxemia during the initial phase of gut decontamination. The amount of endotoxin translocating from the digestive tract to the circ ulation varies with the agents used. Polymyxin only partially reduced the o bserved endotoxin leakage from the gut.