Microbial growth in clinically used enteral delivery systems
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Abstract:
Potential contamination of enteral formulas has led to the development of policies limiting formula hangtimes. However, enteral administration bags can easily become contaminated during formula refilling. We prospectively studied enteral formula contamination when the hangtime of a prefilled 1000 ml pouch was compared with the standard 4-hour hangtime of a refilled enteral administration bag. Samples of formula collected from different locations along the enteral delivery system were cultured during 57 days of enteral hyperalimentation in 19 patients. The overall enteral formula contamination rate was 61%, where the greatest microbial growth occurred in reconstituted enteral formulas. The presence of microbial growth did not differ between canned formulas administered according to a 4-hour hangtime and the prefilled pouch. Greatest growth in all cases was at the distal tubing hub, where contamination during system manipulation or from the patient probably occurred. Use of prefilled enteral administration bags may delay formula contamination in the administration reservoir. A change in equipment design that would decrease the need to manipulate feeding sets or feeding tube connections should be further investigated.
Insights
Enteral formula contamination is common, occurring in 61% of samples, especially in reconstituted formulas. Prefilled bags may delay contamination compared to refilled bags, but distal tubing remains a key contamination site.
Area of Science:
- Microbiology
- Clinical Nutrition
- Infection Control
Background:
- Enteral formula contamination poses a risk, leading to policies limiting formula hangtimes.
- Refilling enteral administration bags can introduce contamination.
- The efficacy of prefilled pouches versus refilled bags in preventing contamination requires investigation.
Purpose of the Study:
- To compare enteral formula contamination rates between prefilled pouches and standard refilled administration bags.
- To identify key sites of microbial growth within the enteral delivery system.
Main Methods:
- Prospective study over 57 days involving 19 patients receiving enteral hyperalimentation.
- Culturing of enteral formula samples from various points in the delivery system.
- Comparison of contamination in prefilled 1000 ml pouches versus refilled bags with a 4-hour hangtime.
Main Results:
- Overall enteral formula contamination rate was 61%.
- Greatest microbial growth occurred in reconstituted enteral formulas.
- No significant difference in contamination was found between canned formulas (4-hour hangtime) and prefilled pouches.
- Highest microbial growth was consistently observed at the distal tubing hub.
Conclusions:
- Prefilled enteral administration bags may delay contamination in the administration reservoir.
- Contamination likely occurs during system manipulation or from the patient, particularly at the distal tubing hub.
- Further investigation into equipment design to minimize manipulation of feeding sets and connections is recommended.