BACTERIAL TRANSLOCATION AFTER BURN INJURY - THE CONTRIBUTION OF ISCHEMIA AND PERMEABILITY CHANGES

Bacterial translocation (BT) has been shown to occur in stress and trauma. In this study, we examined the contribution of altered intestinal permeability (measured with Cr-51-EDTA) and intestinal blood flow (radioactive microspheres) to the loss of intestinal barrier function after burn injury. A 42.6 +/- 0.6% total body surface area scald burn was produced in Sprague-Dawley rats; sham burn animals served as controls. Rats (29 burn and 20 sham burn) were sacrificed 24 h postburn, and mesenteric nodes (MLN), cecum, spleen, and liver were cultured. The incidence of BT was significantly higher in burn compared to shams (MLN, 55 vs. 15%; spleen, 31 vs. 10%; liver, 31 vs. 10%; p < .05). Cecal concentration of Gram-negative bacteria were similar in all rats (5.2 +/- 0.2 X 10(8) colony forming units/g). 5 h postburn, intestinal blood flow decreased significantly in burn (1.60 +/- .20) compared to shams (2.49 +/- .24 ml/min/g, p = .01); at this time, plasma to luminal clearance of Cr-51-EDTA was greater in the burn (.146 +/- .033, N = 9) than in shams (.050 +/- .010 ml/min/100 g, N = 9, p = .001); 24 h postburn, there was no significant difference in intestinal blood flow in sham (2.86 +/- .46, N = 10) and burn rats (2.29 +/- .44 ml/min/g, N = 11); plasma to intestinal lumen clearance of Cr-51-EDTA was similar in sham (.054 +/- .010, N = 11) and burn rats (.051 +/- .006 ml/min/100 g, N = 12) 24 h postburn. These data confirm that after a major cutaneous burn, bacteria indigenous to the gut can translocate out of the intestine to systemic organs; loss of gut barrier function is related to transient intestinal hypoperfusion and increased intestinal permeability after burn injury.