Growth of Microorganisms in Total Parenteral Nutrition Solutions Without Lipid

Abstract

Background: To identify the microorganisms that can grow rapidly in total parenteral nutrition (TPN) solutions, we investigated the growth of the major causes of catheter-related blood stream infection (Staphylococcus aureus, Serratia marcescens, Bacillus cereus, and Candida albicans) in TPN solutions without lipid. Methods: Experiment 1: A commercial TPN solution without lipid containing multivitamins (pH5.6) was used. A specific number of each test microorganism was added to each 10 mL of the TPN solution and incubated at room temperature. An aliquot of test solution was sampled and inoculated to SCD agar plates at 0, 24, and 48 hrs after the addition of the microorganisms. The number of microorganisms was counted as colony forming units. Experiment 2: The other 2 commercial TPN solutions without lipid (pH5.5) were supplemented with multivitamins. The pH values of the solutions were adjusted to about 6.0, 6.5, or 7.0 using 0.5 mol/L NaOH. The addition of microorganisms, incubation, and counting were performed in the same manner. Results: Experiment 1: S. aureus, S. marcescens, and B. cereus did not increase in the TPN solution without lipid containing multivitamins (pH5.6), but C. albicans increased rapidly. Experiment 2: The 3 bacterial species did not increase even at pH6.0, but increased at pH6.5 and increased rapidly at pH7.0 in both TPN solutions. C. albicans increased similarly at any pH. Conclusion: These results suggest that bacterial species cannot grow in TPN solutions without lipid due to the acidity (pH5.6 or lower), but Candida species can grow regardless of the acidity.

Growth of Microorganisms in Total Parenteral Nutrition Solutions Containing Lipid

“…In AT1V, the standard strains of S. aureus, S. marcescens and B. cereus did not increase at pH 5.9 as well as at the original pH of 5.5 but increased slowly at pH 6.3 and increased rapidly at pH 6.8 (Figures 6-8), similar to the results of our previous study 10…”

“…Likewise, we have previously confirmed that while bacterial species do not grow in TPN solutions without lipid, Candida species grow rapidly 10. Our data have shown that bacterial species cannot grow due to the acidity, but Candida species can grow regardless of the acidity 10. In contrast, most microorganisms grow rapidly in commercial lipid emulsions,11-15 and sporadic CRBSI and outbreaks have been traced to contaminated lipid emulsion 16,17.…”

“…Total parenteral nutrition (TPN) solutions are considered to be relatively good growth media for microorganisms,1,4 whereas a number of investigators have shown that TPN solutions are poor growth media for most microorganisms that cause CRBSI, with the exception of Candida species 5-9. Likewise, we have previously confirmed that while bacterial species do not grow in TPN solutions without lipid, Candida species grow rapidly 10. Our data have shown that bacterial species cannot grow due to the acidity, but Candida species can grow regardless of the acidity 10.…”

“…Furthermore, blood stream infection outbreaks of Bacillus cereus via intravenous line were recently reported in Japan 20. In the present study, we investigated the growth in TPN solutions containing lipid of the same microorganisms studied previously:10 ie, Staphylococcus aureus as a delegate of gram positive cocci, Serratia marcescens as a delegate of gram negative rods, Bacillus cereus as a delegate of gram positive rods, and Candida albicans as a delegate of fungi. To clarify whether the acidity of TPN solutions suppresses microbial growth in the presence of lipid, the growth of all strains employed were investigated at various pH values in a commercial TPN solution containing lipid in the first experiment.…”

Mycological Analysis and Potential Health Hazards of Dextrose Intravenous Infusions in Nigeria.

“…Parenteral nutritions and Intravenous fat emulsions can become contaminated during preparation and infusion, with fungal pathogens (Kuwahara, et al, 2010) especially Candida species which accounts for 20 -30 % of systemic infections associated with Central venous catheters. Candida albicans has the ability to either grow very well or sustain prolonged viability in all nutritional intravenous products.…”