Microbial growth in clinically used enteral delivery systems.

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.