Related Experiment Videos
Growth of Staphylococcus aureus in four intravenous anesthetics
1Department of Anesthesiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612.
Abstract:
Patient infections related to the use of propofol have been reported. To investigate the growth of Staphylococcus aureus in propofol, thiopental, methohexital, etomidate, and 0.9% saline containing no bacteriostatic drug, these preparations were inoculated and samples were plated onto blood agar at 0, 3, 6, 21, 24, and 27 h. The number of colony-forming units (CFU) on the plates was then determined after 24 h of incubation. Samples from the inoculated etomidate solution showed zero CFU at 3 h and thereafter, whereas 21 h were required by the methohexital and thiopental solutions to reduce the number of CFU to zero. For normal saline, no significant change in CFU was seen before the first 6 h, then the number of CFU gradually declined, although some S. aureus CFU were still present at 27 h. Inoculation of the propofol emulsion resulted in a substantial growth of S. aureus between 6 and 21 h after inoculation. We conclude that, of the preparations tested, only propofol was an excellent medium for the rapid growth of S. aureus. Meticulous sterile technique, therefore, is advised when handling it.
Insights
Propofol supports rapid Staphylococcus aureus growth, unlike other anesthetics or saline. Strict sterile techniques are crucial when handling propofol to prevent patient infections.
Area of Science:
- Anesthesiology
- Microbiology
- Infection Control
Background:
- Patient infections linked to propofol use have been documented.
- Understanding microbial growth in anesthetic agents is critical for patient safety.
Purpose of the Study:
- To investigate the in vitro growth of Staphylococcus aureus in propofol.
- To compare S. aureus growth in propofol versus other anesthetics (thiopental, methohexital, etomidate) and 0.9% saline.
Main Methods:
- Inoculation of propofol, thiopental, methohexital, etomidate, and 0.9% saline with Staphylococcus aureus.
- Sampling at multiple time points (0, 3, 6, 21, 24, 27 hours) and plating on blood agar.
- Determination of colony-forming units (CFU) after 24-hour incubation.
Main Results:
- Propofol demonstrated substantial S. aureus growth between 6 and 21 hours post-inoculation.
- Etomidate showed rapid bacterial elimination (zero CFU by 3 hours).
- Methohexital and thiopental required 21 hours for complete bacterial elimination.
- 0.9% saline showed a gradual decline in CFU, with some remaining at 27 hours.
Conclusions:
- Propofol serves as an excellent growth medium for Staphylococcus aureus.
- Rigorous sterile techniques are essential during propofol handling to mitigate infection risks.