Original contribution Antibacterial activity of remifentanil and mixtures of remifentanil and propofol Teoman Zafer Apan MD, PhD (Assistant Professor) a, ⁎ , Alpaslan Apan MD (Associate Professor) b , Şaziye Şahin MD (Associate Professor) b , Mehmet Çakırca MD (Assistant) b a Department of Microbiology, Kirikkale University Faculty of Medicine Kirikkale 71100, Turkey b Department of Anesthesiology, Kirikkale University Faculty of Medicine, Kirikkale 71100, Turkey Received 15 July 2006; revised 31 January 2007; accepted 2 February 2007 Abstract Study Objective: To investigate the antibacterial activity of glycine, which is contained in remifentanil, when combined with propofol. Design: Prospective study. Setting: Departments of anesthesiology and microbiology of a university hospital. Measurements: Growth of the microorganisms Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans in propofol 1%; saline dilutions of remifentanil at one-, 10-, and 100-μg/mL concentrations; and 1:1 mixtures of propofol with remifentanil solutions was determined. Main Results: Remifentanil inhibits bacterial growth in a concentration-dependent manner. The antibacterial effects were more pronounced with Staphylococcus aureus and Pseudomonas aeruginosa at cultures obtained at the fifth hour. The inhibition of bacterial growth was less influenced with Escher- ichia coli and Candida albicans. Conclusions: Propofol and remifentanil mixtures decreased bacterial growth, and combinations may reduce the infectious complications from accidentally contaminated propofol. Crown Copyright © 2007 Published by Elsevier Inc. All rights reserved. Keywords: Anesthetic; Intravenous; Propofol; Remifentanil; Bacterial growth 1. Introduction Propofol (2,6-diisopropylphenol) is a popular drug for induction and maintenance of anesthesia. However, the lipid content is a medium for bacterial growth. In a multicenter survey, propofol was implicated as the source of post- operative infections with severe consequences [1]. Outbreaks were reported with various microorganisms, with serious or fatal outcomes, which were associated with improper care on preparation [2], delay in administration [3], or more than one administration [4]. Trépainer and Lessard recently deter- mined that there were many reports of systemic infections ⁎ Corresponding author. Tel.: +90 3123258006; fax: +90 3122522625; GSM: +90 533 2235034. E-mail address: teomanapan@yahoo.com (T.Z. Apan). 0952-8180/$ – see front matter Crown Copyright © 2007 Published by Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2007.02.005 Journal of Clinical Anesthesia (2007) 19, 346–350