Microbiological evaluation of four enteral feeding systems which have been deliberately subjected to faulty handling procedures.

The present study was designed to investigate the levels of contamination in four currently used 1000 mL, 'ready-to-hang', enteral feeding systems--Osmolite (Ross Ready-To-Hang), Steriflo, Dripac-flex and Easybag, when faulty handling procedures were used during assembly of the systems. The top of the nutrient container and the proximal (container) end of the pump set of each system were touched during assembly by a researcher whose hands had been deliberately contaminated with Klebsiella aerogenes. Once assembled systems were run continuously for 24 h delivering 1000 mL of feed. Feed samples for microbiological analysis were taken from the distal (patient) end of the feeding tube at 0 h and 24 h and from the feed remaining in the nutrient container at the end of administration (24 h). Five systems of each type were run. Five controls were also run for each type of system, where all procedures were carried out wearing sterile gloves. Eighty-seven percent of feed samples collected from the Osmolite systems and 80% of those from the Steriflo systems were found to contain K. aerogenes, with 13% of feed samples from both systems containing > or = 10(4) cfu/mL, a level of contamination, considered by many, as that above which feed is unacceptable for patient consumption. The percentage of feed systems containing the test organism was much lower in the Dripac-flex and Easybag systems, with K. aerogenes being detected in 27% and 13% of samples respectively. No feed samples from either of these systems contained > or = 10(4) cfu/mL. From the results it can be concluded that deviation from the manufacturers instructions when assembling enteral feeding systems can lead to bacterial contamination of these systems. The results also highlight the effect that system design, such as recessed pump set spikes and recessed nutrient container seals (both of which prevent care workers accidentally touching parts of the feeding system which may come into contact with the feed) have on reducing the number of bacteria gaining entry to the feed in the systems.