Environmental Contamination of Continuous Drip Feedings

Abstract

Continuous gastric and transpyloric feeding techniques have been advocated for low birth weight infants, but bacterial surveillance studies of these systems have not been reported. A preliminary investigation in our nursery showed that 176(33%) of 576 formula samples obtained from the drip chaimber were contaminated. Using the same feeding system with a broth of Escherichia coil simulating the infant's stomach, none of 83 specimens of formula was contaminated, thereby eliminating the ascending route as the bacterial source. Five of 142 bottles of formula that were opened and exposed to room air for eight hours grew positive cultures. A prospective study of 115 infants showed that 354 (36%) of 976 cultures grown from material taken from formula drip chambers were positive; the presence of a vacuum flutter valve in the reservoir and the number of times formula was added to the chamber did not significantly affect the incidence of positive cultures. Milk reservoirs changed every 24 hours did not have a significantly different contamination rate from those changed every 12 hours. Results of cultures grown from organisms taken from the hands of nurses on the intensive care unit showed a high incidence of organisms that were similar to those cultured from the feeding chambers. This study demonstrates a very high rate of bacterial contamination of infant formulas administered by continuous drip and emphasizes the need for meticulous care in formula-handling techniques.