The Growth of Microorganisms in Total Parenteral Nutrition Admixtures

Abstract

Total nutrient admixtures (TNAs) containing glucose, amino acids, and lipid emulsion in one container and amino acid/dextrose solutions [conventional total parenteral nutrition (TPN) formulations] were studied in a controlled laboratory experiment for their ability to support the growth of microorganisms. Both TNA and conventional TPN formulations for peripheral and central venous administration with standard additives were inoculated with microorganisms to provide 10(1)-10(2) colony-forming units/ml (CFU/ml) of Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans. The admixtures were stored at room temperature and samples for quantitative microbiology were taken at time 0, 6, 12, 24, 48, 72, and 96 hr. K. pneumoniae, E. coli, and P. aeruginosa were able to proliferate in central TNAs, but the growth of these organisms was retarded in conventional TPN solutions. In the peripheral formulations, K. pneumoniae and E. coli proliferated in both the TNA and conventional TPN systems, whereas P. aeruginosa grew well only in the peripheral TNA. S. epidermidis was not able to grow in any admixtures tested; however, C. albicans grew well in all admixtures, but growth was slower in the conventional central TPN. In conclusion, peripheral and central TNAs supported the growth of microorganisms significantly better than conventional TPN solutions.

Parenteral Lipid Emulsion Induces Germination ofCandida albicansand Increases Biofilm Formation on Medical Catheter Surfaces

“…With regard to the growth of C. albicans in parenteral LE, our finding agree with those of several studies [27][28][29][30][31][32][33][34][35][36]40], including those on which clinical guidelines for administration of LE to patients via medical catheters are based [27][28][29][30][31][33][34][35]. However, our finding expand the understanding of the behavior of C. albicans in LE by demonstrating that exposure to LE also induces germination.…”

“…Furthermore, because of the association between fungemia and the administration of parenteral LE, HICPAC guidelines recommend completing infusion of LEs within 12 h and replacing tubing used to administer LEs within 24 h-as opposed to 72 h for solutions containing only dextrose and amino acids [26]. These recommendations are based on prior observations that Candida species are able to grow in LEs [27][28][29][30][31][32][33][34][35][36]. However, the effect of LE on the ability of Candida to form biofilm on medical catheters is unknown.…”

Parenteral Administration of Medium- but Not Long-Chain Lipid Emulsions May Increase the Risk for Infections byCandida albicans

“…Previous in vitro studies with LCT showed that Candida grows better in a lipid-rich environment (5,11,24,36). We did not find a growth-enhancing effect on Candida for parenteral LCT, suggesting that with its metabolic breakdown, the effects of LCT on candidal growth disappear, in contrast with what occurs with MCT.…”

Clinical experience with a lipid‐free, ready‐made parenteral nutrition solution in dogs: 70 cases (2006–2012)

“…In a more recent report, although 62% of dogs were hypertriglyceridemic during PN administration, only 1 out of 14 dogs developed this problem without being hypertriglyceridemic before PN administration . Lipid emulsions may also support bacterial and fungal growth because of their isotonicity and neutral pH, although compounding standards have greatly reduced the risk for contamination …”