IMPACT OF BLOOD-TRANSFUSION AND BURN INJURY ON MICROBIAL TRANSLOCATION AND BACTERIAL SURVIVAL

The role of the immune system in microbial translocation must be clarified. In these studies, the effect of blood transfusion-related immunosuppression on translocation was investigated in a burn animal model previously known to increase the gut's permeability to C-14-radiolabeled Escherichia coli. In a first experiment, Balb/c mice underwent transfusion (T) with 0.2 mL per mouse of allogeneic C3H/HeJ mouse blood 5 days prior to undergoing 30-percent burn injury (B) and simultaneous gavage (G) with 10(9) E. coli bacteria labeled with C-14. An additional six groups of Balb/c mice underwent different combinations of T, B, and G procedures (TG, BG, TB, T, B, G). Survival rate was recorded for all groups on Day 10. This experiment suggested that B and T, to a lesser extent, were the factors affecting survival, although the combination of T, B, and G clearly showed a synergistic effect on mortality. In a second experiment, 18 Balb/c mice belonging to TBG, BG, TG, and G groups were sacrificed 1, 4, and 24 hours after burn or gavage. The residual radioactivity and the percentage of viable bacteria were computed for mesenteric lymph nodes, spleen, liver, lungs, blood, and peritonal fluid. Statistical analysis of the radionuclide counts recognized B as the only variable able to enhance the magnitude of C-14 E. coli translocation. The percentage of viable bacteria showed that T and, more moderately, B were the factors leading to the failure of bacterial clearance in the tissues.