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Published on: September 20, 2019
Growth of microorganisms in total parenteral nutrition solutions containing lipid
Takashi Kuwahara1, Kazuyuki Shimono, Shinya Kaneda
1Preclinical Assessment Department, Otsuka Pharmaceutical Factory, Inc., Tokushima, Japan. kuwahat2@otsukakj.co.jp
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 NaHSO(3)) 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 NaHSO(3)) 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 NaHSO(3), 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 NaHSO(3).
Conclusions:
These results suggest that Candida species can grow rapidly in almost all TPN solutions regardless of the acidity, lipid, and NaHSO(3); 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.
Insights
Candida species rapidly grow in total parenteral nutrition (TPN) solutions. Bacterial growth in TPN is inhibited at pH 5.0 or less, especially with higher sodium bisulfite concentrations.
Area of Science:
- Microbiology
- Clinical Pharmacy
- Infectious Diseases
Background:
- Total parenteral nutrition (TPN) solutions can support rapid microbial growth.
- Catheter-related bloodstream infections (CRBSIs) are a significant risk in patients receiving TPN.
- Common CRBSI pathogens include Staphylococcus aureus, Serratia marcescens, Bacillus cereus, and Candida albicans.
Purpose of the Study:
- To investigate the growth characteristics of key CRBSI pathogens in TPN solutions with varying pH and sodium bisulfite (NaHSO3) concentrations.
- To determine the optimal conditions for microbial proliferation within lipid-containing TPN formulations.
Main Methods:
- Lipid-containing TPN solutions were prepared with two different NaHSO3 concentrations (20 ppm and 400 ppm).
- The pH of these solutions was adjusted to a range of values (4.9–6.8).
- Known quantities of S. aureus, S. marcescens, B. cereus, and C. albicans were inoculated, and their growth was monitored over 48 hours.
Main Results:
- Candida albicans demonstrated rapid growth across all tested pH levels and TPN formulations.
- Bacterial growth was significant at pH 6.0 in TPN with 20 ppm NaHSO3 but was inhibited at lower pH values, ceasing at pH 4.9.
- In TPN with 400 ppm NaHSO3, bacterial growth was suppressed even at pH 5.9.
Conclusions:
- Candida species exhibit robust growth in TPN solutions irrespective of acidity, lipid content, or NaHSO3 levels.
- Bacterial proliferation in lipid-containing TPN is significantly limited at pH 5.0 or below.
- Routine testing of TPN solutions for potential bacterial proliferation is recommended to mitigate infection risks.
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