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Inhibition of bacterial growth by lignocaine in propofol emulsion
Z Ozer1, C Ozturk, A A Altunkan
1Department of Anaesthesiology and Reanimation, Mersin University Medical Faculty, Turkey.
Abstract:
Contamination of propofol, in an emulsion formulation, has been associated with infective complications. Local anaesthetics,some of which are known to have antibacterial properties, are frequently added to the solution to reduce pain on injection. We examined the growth rates of E. coli, S. aureus, S. epidermidis and P. aeruginosa in propofol with and without lignocaine 0.1%-2% after incubation for 2, 5 and 24 hours at 37 degrees C. Growth of microorganisms in each solution was compared by counting the number of colony forming units (CFU). Propofol supported the growth of all microorganisms. An increase in the number of CFUs was observed in all drug combinations 2, 5 and 24 hours after inoculation except for S. aureus (P<0.05). No difference was found in CFU numbers between 2 and 5 hours for this microorganism. With E. coli, a significant decline in colony counts was observed in mixtures of 1% and 2% lignocaine (P<0.05). With the other microorganisms only 2% lignocaine showed a significant reduction in the number of CFUs (P<0.05). We conclude that lignocaine in recommended clinical doses (0.05%-0.1%) did not exhibit adequate antibacterial activity to prevent infective complications.
Insights
Lignocaine, commonly added to propofol to reduce injection pain, did not prevent bacterial growth in this study. Even at higher concentrations, lignocaine showed limited antibacterial activity against common pathogens, raising concerns for infection prevention.
Area of Science:
- Microbiology
- Anesthesiology
- Pharmaceutical Sciences
Background:
- Propofol emulsion contamination is linked to infections.
- Local anesthetics like lignocaine are added to propofol to mitigate injection pain.
- Some local anesthetics possess antibacterial properties, suggesting potential for infection control.
Purpose of the Study:
- To evaluate the antibacterial efficacy of lignocaine in propofol.
- To determine if lignocaine prevents the growth of common bacteria in propofol formulations.
- To assess the impact of varying lignocaine concentrations on bacterial proliferation.
Main Methods:
- Bacterial growth rates of E. coli, S. aureus, S. epidermidis, and P. aeruginosa were assessed.
- Microorganisms were incubated in propofol with and without lignocaine (0.1%-2%) at 37°C for 2, 5, and 24 hours.
- Bacterial growth was quantified by counting colony-forming units (CFUs).
Main Results:
- Propofol alone supported the growth of all tested microorganisms.
- Lignocaine exhibited limited antibacterial activity; only 2% concentration significantly reduced CFUs for most bacteria.
- Recommended clinical doses of lignocaine (0.05%-0.1%) did not prevent bacterial growth.
Conclusions:
- Lignocaine at clinical concentrations does not possess sufficient antibacterial activity to prevent propofol-related infections.
- The addition of lignocaine to propofol does not appear to enhance its antimicrobial properties significantly.
- Further strategies are needed to address the risk of infective complications associated with propofol emulsion.