ANTIMICROBIAL PROPERTIES OF LOCAL ANAESTHETIC BUPIVACAINE IN COMBINATION WITH GENTAMICIN

It has been reported that some of the local anaesthetic agents possess antimicrobial activity against clinically-significant bacteria. Although bupivacaine exhibits a bacteriostatic effect at concentrations above 0.25% there are concerns that it might interact with some of the other antibiotics administered to patients. Whilst these interactions may be potentially benign, the risk is that they are antagonistic and that local bupivacaine might predispose the patient to a higher risk of infection.Bupivacaine is commonly administered as a local anaesthetic following knee arthroplasy; the purpose of this study was to assess its potential interactions with gentamicin eluting from the cement used to fix the device.A strain of Saphylococcus aureus (29213) with established susceptible Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) for gentamicin was used. This organism was inoculated into four types of broth; Mueller-Hinton broth (MH), MH with different concentrations of genta...