Ozlem KocaturkAdnan Menderes University, Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, Division of Anesthesiology, Aydin, Turkey
BACKGROUND AND AIM: Dexmedetomidine and midazolam are commonly used for sedation by infusion in intensive care units. The antibacterial properties of midazolam have been previously described. The aim of this in vitro study was to investigate the antimicrobial effects of dexmedetomidine, midazolam and their buffered solutions with bicarbonate.
METHODS: Diluted and buffered forms (25, 50, 100 mEq/L) of dexmedetomidine and midazolam were prepared. Antimicrobial effect was tested on Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus epidermidis, Candida albicans and Candida Utilis by disc diffusion method and broth microdilution method. The diameters of the inhibition zones and MIC values of test solutions were measured (fig. 1,2).
RESULTS: Dexmedetomidine showed an inhibitor effect on S. aureus, E. Coli, E. faecalis and P. Aeruginosa at concentrations of 64 µg/ml and above. Antimicrobial effect of midazolam on S. Aureus, E. Coli, E. Faecalis, K. Pneumoniae and P. Aeruginosa was observed at concentrations of 128 mg/ml and above. The antimicrobial effect of dexmedetomidine increased with the addition of bicarbonate but midazolam was not affected.
CONCLUSIONS: This is the first study to investigate the antibacterial effectiveness of buffered dexmedetomidine and midazolam. We are of opinion that adding bicarbonate to dexmedetomidine may be beneficial in preventing contamination, especially in intensive care patients. Dexmedetomidine has shown to have antimicrobial properties as midazolam on some microorganisms frequently encountered in hospital invironment. This antimicrobial efficacy which is concentration-dependent can be enhanced by buffering with bicarbonate.