Determining the efficacy of hand sanitizers against virulent nosocomial infections

The goal of this study was to determine the effectiveness of 0.13% benzalkonium chloride (BAC) (Steirolotion), 100% ethanol, and 70% ethyl alcohol (Purell) hand sanitizer in subduing the growth of nosocomial bacteria - methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus (VRE), and Pseudomonas aeruginosa (P. aeruginosa) - when plated on culture media over an extended period of time. In addition, our objective was to quantify the length of time these hand sanitizer agents remained effective, and to extrapolate their efficacy in decreasing the transmission of hospital-acquired infections. 50 microliters of either BAC, 100% ethanol, or 70% ethyl alcohol hand gel sanitizer were pipetted onto Trypticase soy agar with 5% sheep blood plates that were cultured with either MRSA, VRE, or P. aeruginosa. The plates were then incubated at 37.0?. The zone of inhibition (ZOI) was measured daily for 5 days and additionally zones were noted whether or not regrowth recurred in areas where previous growth had initially been inhibited. BAC was found to be superior to both 100% ethanol and 70% ethyl alcohol in the inhibition of MRSA over all time points (p values < .05). BAC was found to be superior to 70% ethyl alcohol in the inhibition of VRE over all time points (p values < .05), but not statistically superior to 100% ethanol against the inhibition of VRE over any time points. BAC was found to be superior to 70% ethyl alcohol and 100% ethanol in the inhibition of pseudomonas over 72 and 24 hours, respectively (p values < .05). The results of this study demonstrate in vitro efficacy of BAC of preventing regrowth of common nosocomial bacteria over a prolonged period of time, especially when compared to ethyl alcohol. Further study is warranted to determine in vivo effectiveness of this formulation of BAC as well as the appropriate time frame of application for effectiveness against P. aeruginosa.