Confirmation of translocated gastrointestinal bacteria in a neonatal model

Purpose. The hypothesis that enteric bacteria translocate from the gastroin testinal (GI) tract to extraintestinal sites has been extensively studied. However, definitive evidence that spontaneous bacterial translocation and d issemination from the GI tract to extraintestinal sites occur in a neonatal model has been lacking. The aim of this study was to confirm this phenomen on by tracking enterally administered, plasmid-labeled bacteria to extraint estinal sites. Materials and Methods. Escherichia coli 07:K1 (E. coli K1) with and without a nontransferable, ampicillin resistance plasmid (pGEM-7) were used in thi s study. Newborn New Zealand white rabbit pups were separated into three tr eatment groups: transformed E. coli K1 (E. coli K1 + pGEM-7, n = 20), nontr ansformed E. coli K1 (n = 12), and control pups (no bacteria, n = 7). Pups were enterally fed 10% Formulac solution supplemented with a suspension of bacteria respective to their group. After the pups fed twice daily for 2 da ys, representative tissue specimens from the small bowel (SB), mesenteric l ymph nodes (MLNs), spleen (SPL), and liver (LIV) were aseptically harvested and tested for culture growth in ampicillin-supplemented medium. Results. Positive growths of plasmid-induced ampicillin-resistant bacteria were detected in tissue specimens harvested from rabbits fed transformed E. coli K1, but were not detected in the other groups. Conclusion. This experiment demonstrated conclusively that transformed E. c oli K1 fed to healthy rabbit pups spontaneously translocated from the intes tinal lumen and subsequently disseminated to the mesenteric lymph nodes, sp leen, and liver. (C) 1999 Academic Press.