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Contamination of enteral nutrition systems during prolonged intermittent use
J E Grunow1, J C Christenson, D Moutos
1Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City.
Abstract:
Two related studies were done to determine the incidence of bacterial contamination in enteral delivery systems that were used for 15 and 7.5 hr, rinsed after each use, and reused daily in vitro for 7 and 5 days, respectively. In the first study, systems infusing either a premixed formula (Ensure) or a hand-mixed formula (Vivonex) did not show bacterial growth until the 4th day, 1.0-2.0 X 10 colony-forming units per milliliter (CFU/ml) of Staphylococcus epidermidis. Thereafter there was sporadic growth of different organisms but never increasing growth during the 7 days of infusion. In the second study, systems with Ensure were initially contaminated with Staphylococcus aureus and Escherichia coli and reused for 5 days. S. aureus was eliminated by rinsing, but E. coli persisted in the delivery system at concentrations of 10(3)-10(6) CFU/ml. We conclude that clean enteral nutrition systems can be rinsed after short-infusion periods and reused up to 7 days in vitro without significant contamination; however, once a bag has become heavily contaminated some bacteria cannot be eradicated from the system by rinsing.
Insights
Clean enteral nutrition systems can be reused for up to 7 days in vitro without significant bacterial contamination. However, heavy contamination may lead to persistent bacteria that rinsing cannot fully eradicate.
Area of Science:
- Microbiology
- Clinical Nutrition
- Infectious Disease Prevention
Background:
- Enteral nutrition is crucial for patients unable to consume food orally.
- Reusable enteral delivery systems require proper cleaning protocols to prevent microbial contamination.
- Bacterial contamination of enteral feeding systems poses a risk of healthcare-associated infections.
Purpose of the Study:
- To assess bacterial contamination incidence in reused enteral delivery systems.
- To determine the efficacy of rinsing in preventing bacterial growth in these systems.
- To evaluate the impact of infusion duration and formula type on contamination levels.
Main Methods:
- In vitro studies simulating daily reuse of enteral delivery systems for 7 and 5 days.
- Systems were rinsed after each use.
- Bacterial contamination was monitored using colony-forming unit (CFU) counts.
- Specific bacteria like Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli were used.
Main Results:
- No significant bacterial growth was observed until day 4 in the first study (Staphylococcus epidermidis).
- Sporadic growth of various organisms occurred but did not increase over 7 days.
- Escherichia coli persisted at high concentrations (10^3-10^6 CFU/ml) after rinsing in the second study, while Staphylococcus aureus was eliminated.
Conclusions:
- Clean enteral nutrition systems, when rinsed after short-infusion periods, can be safely reused in vitro for up to 7 days.
- Heavy contamination of enteral feeding bags can result in persistent bacteria that are resistant to eradication by rinsing alone.