Inactivation of Residual CHG Activity by Thickened Alcohol Solutions

potentially pathogenic microorganisms are removed and destroyed, and second, residual antimicrobial activity is established on the skin. This residual can provide subsequent protection against acquiring or transmitting infection. Often, the use of alcohol products supplements handwashing in healthcare settings. Incompatibility of these antimicrobial products with each other can have a negative impact on efficacy. Method: The test procedure utilized a pigskin in vitro method. Sterile pigskins were washed with a 4% CHG product to establish a CHG residual. The skins were then treated with various 60% (v/v) ethanol solutions thickened with carbomer or hydroxyethyl cellulose. Once the alcohol evaporated, the skins were inoculated with Staphylococcus aureus ATCC 6538. The number of surviving bacteria was enumerated by standard plate count techniques and compared to an untreated control. RESULTS: The CHG residual activity (log REDUCTION = 4.21 stdev 0.52) was not reduced by the treatment of the ethanol solutions either unthickened (4.18 stdev 0.59) or thickened with hydroxyethyl cellulose (4.19 stdev 0.58). The CHG residual activity was significantly reduced by treatment with the ethanol containing carbomer (1.14 stdev 0.85). CONCLUSIONS: The use of ethanol solutions thickened by carbomer in conjunction with CHG wash products may inactivate the residual antibacterial activity of CHG.