Antimicrobial activity of ropivacaine and other local anaesthetics

Background and objective It is claimed that local anaesthetics have antimic robial properties. Our aim was to investigate the antimicrobial effects of different concentrations of ropivacaine, bupivacaine, lidocaine and priloca ine on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Methods All local anaesthetic dilutions were exposed to microorganisms for 0, 30, 60, 120, 240 min at room temperature. The inoculums taken from dilut ed suspensions were reinoculated on blood agar and incubated for 18-24 h at 35 degreesC and then the colonies were counted. Results Ropivacaine did not inhibit any of the microorganisms tested. Bupiv acaine reduced the viable cells of P. aeruginosa at 0.5% and 0.25% solution s. Lidocaine 5% and 2% and prilocaine 2.0% dilutions reduced the viable cel ls of all microorganisms tested. Prilocaine 1.0% reduced the viable cells o f E. coli, S. aureus and P. aeruginosa. Lidocaine 1% reduced only the viabl e cells of P. aeruginosa and prilocaine 0.5% reduced only E. coli. Conclusion Ropivacaine had no antimicrobial effect on microorganisms tested . Bupivacaine showed poor antimicrobial effectiveness. Lidocaine and priloc aine had more powerful antimicrobial effects than the other two local anaes thetics.