Nancy Day Rodgers

Alternative Hand Contamination Technique To Compare the Activities of Antimicrobial and Nonantimicrobial Soaps under Different Test Conditions

ABSTRACT Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log10 counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log10 counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (∼3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log10 counts, compared to the 3.83-log10 reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log10 counts, compared to the 4.22-log10 (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap.

Effect of hand wash agents on controlling the transmission of pathogenic bacteria from hands to food.

The goals of this study were to evaluate the effectiveness of two hand wash regimens in reducing transient bacteria on the skin following a single hand wash and the subsequent transfer of the bacteria to a ready-to-eat food item, freshly cut cantaloupe melon. The number of bacteria recovered from hands and the quantity transferred to the melon were significantly less following the use of an antibacterial soap compared with plain soap. The antimicrobial soap achieved > 3-log reductions versus Escherichia coli and 3.31- and 2.83-log reductions versus Shigella flexneri. The plain soap failed to achieve a 2-log reduction against either organism. The bacteria recovered from the melon handled by hands treated with antimicrobial hand soap averaged 2 log. Melon handled following hand washing with plain soap had > 3 log bacteria in the experiments. Based on previously published feeding studies, an infection rate in the range of approximately 15 to 25% would be expected after ingesting melon containing 2 log CFU compared with ingesting greater than the 3 log transferred from hands washed with plain soap, which would result in a higher infection attack rate of 50 to 80%. The data thus demonstrate there is a greater potential to reduce the transmission and acquisition of disease through the use of an antimicrobial hand wash than through the use of plain soap.

A randomized trial of the efficacy of hand disinfection for prevention of rhinovirus infection.

BACKGROUND Hand disinfection is frequently recommended for prevention of rhinovirus (RV) infection and RV-associated common colds. The effectiveness of this intervention has not been established in a natural setting. The purpose of this study was to determine the effect of hand disinfection on RV infection and RV-associated common cold illness in a natural setting. METHODS A controlled clinical trial was done in young adult volunteers during 9 weeks of the fall 2009 RV season. Volunteers were randomized to either an antiviral hand treatment containing 2% citric acid and 2% malic acid in 62% ethanol (n = 116) or to a no-treatment control group (n = 96). The hand treatment was applied every 3 hours while the subjects were awake. All volunteers kept a daily diary of symptoms and had a nasal lavage for polymerase chain reaction once each week and 2 additional lavages around the time of each common cold illness. The primary endpoint was the number of RV-associated illnesses. The incidence of RV infection and of common cold illnesses were evaluated as secondary endpoints. RESULTS The hand treatment did not significantly reduce RV infection or RV-related common cold illnesses. The total number of common cold illnesses was significantly reduced in the intent-to-treat analysis, but this effect was not seen in the per protocol analysis. CONCLUSIONS In this study, hand disinfection did not reduce RV infection or RV-related common cold illnesses. CLINICAL TRIALS REGISTRATION NCT00993759.

Effectiveness of Hand Sanitizers with and without Organic Acids for Removal of Rhinovirus from Hands

ABSTRACT These studies evaluated the effectiveness of ethanol hand sanitizers with or without organic acids to remove detectable rhinovirus from the hands and prevent experimental rhinovirus infection. Ethanol hand sanitizers were significantly more effective than hand washing with soap and water. The addition of organic acids to the ethanol provided residual virucidal activity that persisted for at least 4 h. Whether these treatments will reduce rhinovirus infection in the natural setting remains to be determined.