Growth of Microorganisms in Total Parenteral Nutrition Solutions Containing 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 containing lipid. Methods: The pH value of a TPN solution containing lipid (pH 6.0, containing 20 ppm of NaHSO3) was adjusted by the addition of HCl to 5.7, 5.4, or 4.9. The pH value of another TPN solution (pH5.5, containing 400 ppm of NaHSO3) was adjusted by the addition of NaOH to 5.9, 6.3, or 6.8. A specific number of each microorganism was added to 10 mL of each test solution and incubated at room temperature. The number of microorganisms was counted as colony forming units at 0, 24, and 48 hrs later. Results: C albicans increased similarly at any pH values in the TPN solution. The bacterial species also increased rapidly at pH6.0 in the solution containing 20 ppm of NaHSO3, but growth was suppressed as the pH value was reduced, with growth halted at pH4.9. However, these bacterial species did not increase, even at pH5.9, in the other solution containing 400 ppm of NaHSO3. Conclusions: These results suggest that Candida species can grow rapidly in almost all TPN solutions regardless of the acidity, lipid, and NaHSO3; also, some bacterial species may grow in TPN solutions containing lipid unless the pH value is 5.0 or less. Therefore, each TPN solution should be examined whether or not the bacterial species can proliferate.

Severe Candida spp. infections: new insights into natural immunity

“…C. albicans makes rather complex metabolically active biofilms consisting of a basal blastospore layer with an overlying matrix of polysaccharides and hyphae [38]. Third, the nature of the infusion fluid, especially when it is parenteral nutrition fluid or highly concentrated sugar solution, contributes to the risk of Candida infection by promoting the growth of the fungus [39].…”

Standardised Parenteral Nutrition

“…In addition, lack of small volume containers, from manufacturers, appropriate for premature infants requires it to be repackaged in the pharmacy. Repackaging of intravenous fat emulsions even using aseptic technique under International Organisation for Standardization (ISO) class 5 conditions was associated with 1.7% rate of contamination [64,65]. 3-in-1 PN preparations may provide some protective effect for lipid emulsion associated BSI.…”

Effects of Lipid Emulsion and Multivitamins on the Growth of Microorganisms in Peripheral Parenteral Nutrition Solutions

“…In clinical practice, PPN solutions are sometimes supplemented with water-soluble vitamins such as B 1 , B 2 , B 6 , B 12 , and C, but rarely supplemented with MV including water-insoluble vitamins. With regard to the pH value of PPN solutions, the physiological pH of Japanese PPN solutions seems to be suitable for bacterial growth,5,6 and B. cereus and S. marcescens can increase rapidly without LE and MV. With regard to BSI, cases with B. cereus and S. marcescens have been reported in PPN patients, while cases with S. aureus , perhaps also with S. epidermidis , have scarcely been reported in PPN patients.…”

“…Since conventional short peripheral catheters are commonly used for PPN and midline catheters or fine-bore long catheters are rarely used in Japan, the pH values of commercial PPN solutions are designed to be greater than 6.5 to prevent infusion phlebitis 3,4. In other words, such physiological pH of PPN solutions are inevitably suitable for bacterial growth and PPN solutions may become a growth medium for bacterial species more than acidic TPN solutions 5,6. Recently, blood stream infection (BSI) outbreaks due to Bacillus cereus or Serratia marcescens in patients receiving PPN have occasionally been reported in Japan,7-10 but these microorganisms are not major causes of catheter-related blood stream infections (CRBSI) observed in TPN patients.…”