In vitro investigation of the antibacterial effect of ketamine.

ABSTRACT

BACKGROUND: Antibacterial activity of local anesthetics especially lidocaine has been shown previously. In this study, the antibacterial effect of ketamine, a general anesthetic agent was investigated. METHODS: The antibacterial effect of ketamine was studied using six different strains of bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Entecoccus faecalis, Streptococcus pyogenes, Pseudomonas aeruginosa and Escherichia coli) with disc diffusion method. Ciprofloxacine discs (CIP, oxoid) were used as a control to verify the methodology. Minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) of ketamine for these bacteria were also determined. RESULTS: No inhibition was evident in discs containing 62.5 microg of ketamine. Ketamine 125 microg showed activity on all the bacteria tested with the exception of E. coli. The inhibition rates of Ketamine were more prominent at the doses of 250 microg and 500 microg similar to the inhibition rate of CIP. Whereas MIC and MBC values of ketamine for S. aureus and S. pyogenes were 500 microg mL(-1), MIC and MBC values for P. aeruginosa were above 2000 microg mL(-1). For other bacteria, these values ranged between these levels. CONCLUSIONS: Ketamine with higher doses showed antibacterial activity. We thought that it will be proper to use ketamine hesitantly in experimental animal studies like sepsis and translocation.