Time-dependent effect of chlorhexidine surgical prep

• Published in: The Journal of hospital infection Vol. 79; no. 4; pp. 313 - 316
• Main Authors: Stinner, D.J, Krueger, C.A, Masini, B.D, Wenke, J.C
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2011; Elsevier
• Subjects: Anti-Infective Agents, Local - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiseptics; Bacterial Load - methods; Biological and medical sciences; Chlorhexidine; Chlorhexidine - pharmacology; Culture Media - chemistry; Dose-Response Relationship, Drug; Drug Stability; General aspects; Human infectious diseases. Experimental studies and models; Infectious Disease; Infectious diseases; Medical sciences; Pharmacology. Drug treatments; Staphylococcus aureus - drug effects; Surgical site infection; Time Factors; Surgical site infection; Chlorhexidine; Surgical wound; Nosocomial infection; Biguanides; Treatment; Surgery; Antiseptic; Guanidines; Disinfecting agent; Public health
• ISSN: 0195-6701; 1532-2939
• DOI: 10.1016/j.jhin.2011.08.016

Summary Despite continued advances in preoperative preventive measures and aseptic technique, surgical site infections remain a problem. The purpose of this study was to evaluate the time-dependent effectiveness of chlorhexidine, a common surgical preparation solution, at various concentrations. Agar plates containing a Mueller–Hinton medium were inoculated with Staphylococcus aureus (lux) bacteria. The bacteria are genetically engineered to emit photons, allowing for quantification with a photon-counting camera system. Standardized amounts of aqueous chlorhexidine at three different concentrations (group 1:4%; group 2:2%; group 3:0.4%) were applied to the agar plates and comparisons in bacterial reduction were made. After 2 min of contact time, groups 1 and 2 had similar reductions in bacterial load with 30% bacterial load remaining in each group ( P = 0.512), whereas group 3 had a significantly higher bacterial load (33%) when compared to both groups 1 and 2 (1 vs 3, P < 0.0001; 2 vs 3, P = 0.0002). The bacterial load in all three groups continued to decrease out to the final time point (1 h) with group 1 having the least amount of bacterial load remaining, 9% ( P < 0.0001) and group 3 with the highest bacterial load remaining, 19% ( P < 0.0001). This study demonstrates two key results: first, dilution of chlorhexidine correlates directly with its bactericidal activity; second, its effectiveness is directly related to its contact time. Based on the results of this study, the authors recommend using 4% chlorhexidine for surgical site preparation and allowing a minimum of 2 min of contact time prior to making the skin incision.