PARENTERAL ANTIBIOTICS AND SELECTIVE INTESTINAL DECONTAMINATION DO NOT PREVENT ENTERIC BACTERIAL OVERGROWTH OR TRANSLOCATION OBSERVED IN A SWINE MODEL OF SMALL-BOWEL TRANSPLANTATION

Alterations in the luminal microflora and increased intestinal translo cation have been reported to occur following experimental and clinical small bowel transplantation (SET). Selective intestinal decontaminati on (SID) has been used to prevent luminal overgrowth and bacterial tra nslocation. Despite the wide use of SID in clinical SET, there are no data supporting its usefulness in this situation. Thus, the aim of thi s investigation was to examine the effects of cyclosporine A (CSA) and SID upon bacterial overgrowth and translocation in a swine model of S ET. Nineteen Large White female pigs weighing 30 +/- 2 kg underwent a total orthotopic SET and were randomly allocated to one of the followi ng experimental groups as follows: Group 1 (No. 8) CSA 25 mg/kg body w eight (b.w.)/day administered subcutaneously and Cefazolin 2 g/day im. Group 2 (No. 6) received the identical immunosuppression but the Cefa zolin 2 g/day im was discontinued on the 5th Postoperative Day (pod) a nd switched to a SID regimen consisting of Vancomycin, 1 g, Nystatin, 500,000 IU, Colistin, 1,500,000 IU, and Tobramycin, 100 mg, given thro ugh a gastrostomy tube. Group 3 (No. 5) received no immunosuppression but antibiotic consisting of Cefazolin 2 g im/day. Group 4 (No. 7) und erwent a small bowel autotransplantation. Group 4 received SID as in g roup 2 but no immunosuppression was given, Finally, 17 normal animals were sham-operated and were used as normal controls (N group). The ani mals in groups 1, 2, and 4 were sacrificed on the 29th pod. Those in g roup 3 were sacrificed on the 7th pod. Samples from graft, native bowe l, liver, kidney, skin, and lungs were processed for histologic evalua tion. Moreover, samples from the graft (proximal, middle, and distal) and adjacent mesenteric lymph nodes were harvested aseptically and cul tured for both aerobes as well as for anaerobes. Significant increases in the number of aerobes and anaerobes were found in the proximal gra ft of all groups studied compared to the normal controls. The rate of intestinal translocation was 19% in the normal controls and increased to 88, 83, 100, and 100% in groups 1, 2, 3, and 4, respectively. Based upon these data, it can be concluded that SID is no better than a par enteral antibiotic regimen at preventing bacterial overgrowth followin g SET. Moreover, neither therapy reduces the high rate of bacterial tr anslocation to mesenteric nodes seen in arrivals following experimenta l SET. (C) 1995 Academic Press, Inc.