dExtrinsically contaminated propofol has been associated with multiple infe
ctious complications. Injection of propofol is associated with pain that is
diminished by the addition of lidocaine. Lidocaine has antibacterial prope
rties at high concentrations, but low concentrations of lidocaine (0.1%) ha
ve not been studied. We examined the growth rates of Staphylococcus aureus,
Serratia marcescens, Pseudomonas aeruginosa, and Candida albicans in propo
fol containing disodium edeteate with and without added lidocaine 0.1% 2, 5
, and 24 h after inoculation. There was no significant difference in the nu
mber of colony-forming units between propofol with and without added lidoca
ine at any time after inoculation. Implications: The addition of Lidocaine
to propofol in concentrations clinically effective in reducing pain on inje
ction had no effect on microbial growth. Adherence to strict aseptic techni
que is further emphasized.