Michael J. Dolan

A close look at alcohol gel as an antimicrobial sanitizing agent

BACKGROUND Hand transmission of microbes by health care workers is a primary cause of nosocomial infections in both long-term and acute care facilities. Compliance with effective handwashing and hand sanitization regimens can break this cycle. METHODS We investigated the antimicrobial efficacy and irritation potential of 5 handwash product regimens: a nonantimicrobial lotion soap, an antimicrobial lotion soap, an alcohol gel sanitizer, a nonantimicrobial lotion soap with an alcohol gel sanitizer, and an antimicrobial lotion soap with an alcohol gel sanitizer. The regimens were evaluated by using a Healthcare Personnel Handwash procedure, and irritation was assessed by using expert hand evaluation after 25 consecutive washes. RESULTS The Healthcare Personnel Handwash data showed that the mean log reductions from baseline were greatest for the lotion soaps with alcohol gel sanitizer, less for the alcohol and the antimicrobial soap alone, and least for the bland soap. All of the product regimens showed a low potential for skin irritation. CONCLUSION In terms of both microorganism reduction and skin irritation, the most effective product regimens were the use of alcohol gel sanitizer in combination with either an antimicrobial or a plain lotion soap.

Bacterial Hand Contamination and Transfer after Use of Contaminated Bulk-Soap-Refillable Dispensers

ABSTRACT Bulk-soap-refillable dispensers are prone to extrinsic bacterial contamination, and recent studies demonstrated that approximately one in four dispensers in public restrooms are contaminated. The purpose of this study was to quantify bacterial hand contamination and transfer after use of contaminated soap under controlled laboratory and in-use conditions in a community setting. Under laboratory conditions using liquid soap experimentally contaminated with 7.51 log10 CFU/ml of Serratia marcescens, an average of 5.28 log10 CFU remained on each hand after washing, and 2.23 log10 CFU was transferred to an agar surface. In an elementary-school-based field study, Gram-negative bacteria on the hands of students and staff increased by 1.42 log10 CFU per hand (26-fold) after washing with soap from contaminated bulk-soap-refillable dispensers. In contrast, washing with soap from dispensers with sealed refills significantly reduced bacteria on hands by 0.30 log10 CFU per hand (2-fold). Additionally, the mean number of Gram-negative bacteria transferred to surfaces after washing with soap from dispensers with sealed-soap refills (0.06 log10 CFU) was significantly lower than the mean number after washing with contaminated bulk-soap-refillable dispensers (0.74 log10 CFU; P < 0.01). Finally, significantly higher levels of Gram-negative bacteria were recovered from students (2.82 log10 CFU per hand) than were recovered from staff (2.22 log10 CFU per hand) after washing with contaminated bulk soap (P < 0.01). These results demonstrate that washing with contaminated soap from bulk-soap-refillable dispensers can increase the number of opportunistic pathogens on the hands and may play a role in the transmission of bacteria in public settings.