ASPIRATION (OF GASTRIC RESIDUALS) - A CAUSE OF BACTERIAL-CONTAMINATION OF ENTERAL FEEDING SYSTEMS

In vitro model enteral feeding systems were used to investigate whethe r bacteria can travel from the 'patient's' stomach or intestine via th e enteral feeding tube to the giving set and nutrient container of the feeding system when feed is flowing continuously through the system f or 24 h. Further systems were also assembled to examine the effects th at aspiration and flushing via the enteral feeding tube and/or the med ication (Y) port have on the bacterial contamination of feed and feedi ng systems. Organisms were detected at levels ranging from 10(2)-10(9) CFU/ml (CFU, colony forming units) in feed samples collected from the distal end of the giving set at 0 h immediately after aspirating or a spirating and flushing. Fewer bacteria (10(2)-10(5) CFU/ml) were recov ered at 0 h in samples from systems where aspiration or aspiration and flushing were carried out via the tube as compared with those where a spiration and flushing took place via the mediport (10(6)-10(9) CFU/ml ). No bacteria were detected at 0 h in samples from systems that had n either been aspirated nor flushed. The test organism, Klebsiella aerog enes was recovered from all samples taken from the distal ends of the giving sets after 24 h. The systems which were neither aspirated nor f lushed yielded more variable levels of contamination (10(4)-10(8) CFU/ ml). The remainder of the systems, which had been subjected to some co mbination of aspirating and hushing, had more consistent levels of con tamination (10(6)-10(8) CFU/ml) after 24 h. At no time during the stud y were K. aerogenes organisms detected in samples of feed taken from t he nutrient container or just below the drip chamber at 24 h. The resu lts of this study confirm the hypothesis that one of the contributory factors in the microbial colonisation of enteral feeding tubes and giv ing sets with organisms from the patients' own nora is the practice of aspirating the stomach or intestinal contents to check the position o f the tube.