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Effect of total parenteral nutrition plus morphine on bacterial translocation in rats
P M Kueppers1, T A Miller, C Y Chen
1Department of Surgery, University of Texas Medical School, Houston.
Objective:
This study tested the hypothesis that gut stasis induced by parenteral morphine sulfate (MS) leads to enhanced bacterial translocation in rats on total parenteral nutrition (TPN).
Summary Background Data:
TPN and MS are common adjuncts in the care of critically ill patients. TPN is known to provoke a variable degree of translocation. MS induces gut stasis with an accompanying bacterial overgrowth. The effect of these two treatments in combination on translocation is not known.
Methods:
Rats were provided with central and subcutaneous lines for the continuous infusion of nutrients and drugs, respectively. Intestinal transit was assessed by the caudal movement of a fluorescent marker intubated into the proximal duodenum. Quantitative bacteriology was carried out from various segments of the gut and from ileocecal mesenteric lymph nodes (MLN), spleen, liver, and systemic blood obtained by cardia puncture on sacrifice at 96 hours.
Results:
Transit was unchanged by TPN alone but prolonged when given in combination with MS. Bacterial overgrowth was also enhanced by MS and increased the bacterial translocation to MLN from 50% of animals with TPN, to 100% in those receiving both TPN and MS; the colony-forming units per MLN increased from 33 +/- 14 with TPN alone to 2079 +/- 811 (STD) with TPN plus MS. Furthermore, no bacteria were found at systemic sites with TPN alone, but in 93.3% of animals receiving TPN and MS. In a subgroup of rates provided with glutamine in TPN, the TPN plus MS effects on translocation were not reversed.
Conclusions:
These observations demonstrate the important role that morphine plays in promoting translocation, presumably by disrupting fasting motility and enhancing bacterial overgrowth.
Insights
Parenteral morphine sulfate combined with total parenteral nutrition significantly increases bacterial translocation in rats. This suggests morphine disrupts gut motility, promoting bacterial overgrowth and systemic spread.
Area of Science:
- Gastroenterology
- Critical Care Medicine
- Microbiology
Background:
- Total parenteral nutrition (TPN) and morphine sulfate (MS) are frequently used in critically ill patients.
- TPN can cause translocation, and MS induces gut stasis and bacterial overgrowth.
- The combined effect of TPN and MS on bacterial translocation was previously unknown.
Purpose of the Study:
- To investigate if gut stasis induced by parenteral morphine sulfate enhances bacterial translocation in rats receiving total parenteral nutrition.
Main Methods:
- Rats received continuous infusions of nutrients and drugs via central and subcutaneous lines.
- Intestinal transit was measured using a fluorescent marker.
- Quantitative bacteriology was performed on gut segments, lymph nodes, spleen, liver, and blood post-sacrifice.
Main Results:
- Morphine sulfate prolonged intestinal transit and enhanced bacterial overgrowth in rats on TPN.
- Bacterial translocation to mesenteric lymph nodes increased from 50% (TPN alone) to 100% (TPN + MS).
- Systemic bacterial presence was observed in 93.3% of rats receiving TPN + MS, versus none with TPN alone.
Conclusions:
- Morphine sulfate plays a critical role in promoting bacterial translocation.
- This effect is likely due to morphine disrupting fasting motility and exacerbating bacterial overgrowth.
- Glutamine supplementation did not reverse the translocation effects of TPN + MS.