The effect of lidocaine on bacterial growth in propofol.

UNLABELLED: Extrinsically contaminated propofol has been associated with multiple infectious complications. Injection of propofol is associated with pain that is diminished by the addition of lidocaine. Lidocaine has antibacterial properties at high concentrations, but low concentrations of lidocaine (0.1%) have not been studied. We examined the growth rates of Staphylococcus aureus, Serratia marcescens, Pseudomonas aeruginosa, and Candida albicans in propofol containing disodium edeteate with and without added lidocaine 0.1% 2, 5, and 24 h after inoculation. There was no significant difference in the number of colony-forming units between propofol with and without added lidocaine at any time after inoculation. IMPLICATIONS: The addition of lidocaine to propofol in concentrations clinically effective in reducing pain on injection had no effect on microbial growth. Adherence to strict aseptic technique is further emphasized.