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Confirmation of translocated gastrointestinal bacteria in a neonatal model
1Section of Pediatric Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
Insights
This study confirms bacterial translocation in neonatal rabbits. Enterally administered, plasmid-labeled E. coli K1 spread from the gut to extraintestinal sites like the spleen and liver.
Area of Science:
- Microbiology
- Neonatal Research
- Gastrointestinal Health
Background:
- Bacterial translocation from the gastrointestinal tract to extraintestinal sites is a known phenomenon.
- However, definitive evidence in neonatal models has been limited.
- This study aimed to confirm spontaneous bacterial translocation in a neonatal setting.
Purpose of the Study:
- To definitively demonstrate spontaneous bacterial translocation and dissemination from the gastrointestinal tract to extraintestinal sites in a neonatal model.
- To track enterally administered, plasmid-labeled bacteria to extraintestinal locations.
- To provide conclusive evidence of this phenomenon in healthy neonates.
Main Methods:
- Utilized plasmid-labeled Escherichia coli O7:K1 (E. coli K1) and non-transformed E. coli K1.
- Newborn New Zealand white rabbit pups were divided into three groups: transformed E. coli K1, non-transformed E. coli K1, and controls.
- Pups received enterally administered bacteria via a formula solution for two days, followed by tissue specimen analysis.
Main Results:
- Plasmid-induced ampicillin-resistant E. coli K1 was detected in tissue specimens from rabbits fed the transformed bacteria.
- No positive bacterial growth was observed in control groups or groups fed non-transformed E. coli K1.
- This indicates successful translocation and dissemination of the labeled bacteria.
Conclusions:
- Conclusively demonstrated spontaneous bacterial translocation of transformed E. coli K1 from the intestinal lumen in healthy rabbit pups.
- Confirmed dissemination of bacteria to mesenteric lymph nodes, spleen, and liver.
- Provides robust evidence for bacterial translocation in a neonatal model.
Purpose:
The hypothesis that enteric bacteria translocate from the gastrointestinal (GI) tract to extraintestinal sites has been extensively studied. However, definitive evidence that spontaneous bacterial translocation and dissemination from the GI tract to extraintestinal sites occur in a neonatal model has been lacking. The aim of this study was to confirm this phenomenon by tracking enterally administered, plasmid-labeled bacteria to extraintestinal sites.
Materials And Methods:
Escherichia coli 07:K1 (E. coli K1) with and without a nontransferable, ampicillin resistance plasmid (pGEM-7) were used in this study. Newborn New Zealand white rabbit pups were separated into three treatment groups: transformed E. coli K1 (E. coli K1 + pGEM-7, n = 20), nontransformed 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 days, representative tissue specimens from the small bowel (SB), mesenteric lymph 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. coli K1 fed to healthy rabbit pups spontaneously translocated from the intestinal lumen and subsequently disseminated to the mesenteric lymph nodes, spleen, and liver.