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Microbiol growth in lipid emulsions used in parenteral nutrition
Abstract:
Parenteral nutrition via central venous catheterization is associated with serious risks, especially that of sepsis. Lipid emulsion (Intralipid[Sweden]), which may be administered peripherally, was evaluated for its potential to support microbial growth. Washed cultures of Staphylococcus aureus, Candida albicans, and three species of Gram-negative rods were all capable of multiplying in the emulsion at room temperature. Variations in inoculum size did not affect the growth rate. Studies comparing the emulsion to amino acid-glucose solutions (total parenteral nutrition [TPN])confirmed other reports that TPN inhibits the growth of certain bacteria but merely retards fungal multiplication. When human serum was added to the lipid emulsion in an attempt to simulate in vivo conditions at the catheter tip, Escherichia coli was inhibited while the growth of S aureus and C albicians was unaltered.
Insights
Lipid emulsions, used in parenteral nutrition, support microbial growth, posing a sepsis risk. This contrasts with total parenteral nutrition solutions, highlighting a critical safety concern for intravenous therapies.
Area of Science:
- Microbiology
- Clinical Nutrition
- Infectious Disease
Background:
- Parenteral nutrition (PN) via central venous catheters carries significant risks, notably sepsis.
- Lipid emulsions are used in PN and can be administered peripherally.
Purpose of the Study:
- To evaluate the potential of lipid emulsion (Intralipid) to support microbial growth.
- To compare microbial growth in lipid emulsion versus total parenteral nutrition (TPN) solutions.
- To assess the impact of human serum on microbial growth in lipid emulsion.
Main Methods:
- Washed cultures of Staphylococcus aureus, Candida albicans, and Gram-negative rods were incubated in lipid emulsion at room temperature.
- Microbial growth rates were compared between lipid emulsion and TPN solutions.
- Escherichia coli, S. aureus, and C. albicans growth was studied in lipid emulsion supplemented with human serum.
Main Results:
- Staphylococcus aureus, Candida albicans, and Gram-negative rods multiplied in lipid emulsion.
- Inoculum size did not influence the growth rate in lipid emulsion.
- TPN solutions inhibited certain bacteria but only retarded fungal growth.
- Human serum inhibited E. coli growth in lipid emulsion but did not affect S. aureus or C. albicans.
Conclusions:
- Lipid emulsions can support the growth of common pathogens, increasing the risk of catheter-related infections.
- Lipid emulsions present a different microbial growth environment compared to TPN solutions.
- The addition of serum partially mitigates bacterial growth but not fungal growth in lipid emulsions.