Bacterial Translocation of Intestinal Pseudomonas aeruginosa in Post-Burn Infection of Mice

The significance of intestinal Pseudomonas aeruginosa as a pathogen of post-burn infection in mice was established. Mice with and without P. aeruginosa intestinal colonization were scorched with a deep dermal burn by ethanol flame on the shaven back, involving approximately 25% of the total body surface area. Eight hours later, P. aeruginosa of a serotype similar to that previously administered (per os) was detected in the burn site, liver, and spleen of P. aeruginosa-treated, but not the control, animals. Within three post-burn days, 33.3% of the P. aeruginosa-treated, burned mice died of infection-derived sepsis, whereas none of the control mice died. In addition, when the orally nonabsorbable antibiotics, polymyxin B (12mg/kg) and vancomycin (30mg/kg), were administered by intragastric injection to P. aeruginosa-treated mice immediately after burn exposure, the mortality rate significantly decreased to 16.1±6.1% compared with 35.0±5.0% in similarly colonized, burned mice not given these oral antibiotics (P<0.05). These findings suggest that P. aeruginosa colonized in the intestinal tract is noxious and can be fatal as a pathogen of post-burn infection. Furthermore, our report suggests that selective digestive decontamination (decontamination of endogenous pathogens in the intestinal tract) is essential in preventing post-burn infection associated with bacterial translocation.