In Vitro Skin Comparison of Alcohol and Non-Alcohol Hand Sanitizers

BACKGROUND/OBJECTIVES: Alcohol hand sanitizers are designed to be safe, fast-acting and effective. Their use in U.S. hospitals has increased dramatically in the past thirty years. Yet, flammability of alcohol solutions and misconceptions about skin drying still lead to questions from healthcare workers about the use of alcohol hand sanitizers. Alcohol-free hand sanitizers, often containing benzalkonium chloride, continue to be marketed to consumers in the retail environment and, in some instances, to healthcare personnel. We used a pigskin model to determine if hand sanitizers containing benzalkonium chloride were effective against Serratia marcescens and warrant evaluation for use in the healthcare environment. METHODS: Three marketed 0.13% benzalkonium chloride hand sanitizers (Products A, B and C) along with two marketed alcohol hand rubs, were tested using the pigskin model. Sterile pigskin pieces were inoculated with S. marcescens ATCC# 14756, and product was then applied to each pair of skins. The treated pigskin pieces were left for a specified contact time. At the end of the contact time, a neutralizing solution was added and the pigskin surface was debrided. Serial dilutions were then performed and plated. Control pigskin pieces were inoculated, neutralized and sampled in the same manner. Plates were incubated 24 hrs at 308C and CFU/mL results were transformed to log10 to calculate average log reductions. RESULTS: In pilot studies, marketed 0.13 % (w/w) benzalkonium chloride hand sanitizers demonstrated an average log reduction against S. marcescens ATCC# 14756 of 1.43 6 0.22 (Product A), 1.40 6 0.29 (Product B) and 1.12 6 0.26 (Product C), respectively (6 SD, n54 pigskins, 2 pairs). A marketed 63% (v/v) isopropanol handrub demonstrated an average log reduction of 3.18 6 0.10 while a marketed 65% (v/v) ethanol handrub demonstrated an average log reduction of 2.76 6 0.40. A solution of only the active ingredient, 0.13%w/w benzalkonium chloride, demonstrated an average log reduction of 1.01 6 0.16. CONCLUSIONS: The results of limited testing using the pigskin model suggest that benzalkonium chloride products are not as effective as an alcohol hand sanitizer. Hand sanitizers are an important component of hand hygiene. American Journal of Infection Control, June 2011.