Comparative efficacy of alcohol-based surgical scrubs: the importance of formulation.

Alcohol-based surgical scrubs (ABSSs) are used to prevent surgical site infections. Chlorhexidine gluconate (CHG) often is added to enhance persistent germicidal activity. The aim of this study was to determine the influence of ABSS product formulation on efficacy. We evaluated three commercially available ABSS formulations and one control alcohol formulation according to the surgical scrub methodology specified by the US Food and Drug Administration (FDA). Only one ABSS formulation met FDA efficacy requirements when tested at the manufacturer's recommended dosage. In contrast, two ABSS formulations, one of which contained CHG, failed to meet the FDA acceptance criteria for a 3-log10 reduction on day 5, meaning the formulations did not sufficiently reduce bacteria levels on hands on the fifth day of product application. The data suggest that recommendations to include CHG in ABSS formulations should be reconsidered, and product efficacy, skin tolerability, and user acceptability should be evaluated on a case-by-case basis.

The relative influences of product volume, delivery format and alcohol concentration on dry-time and efficacy of alcohol-based hand rubs.

BACKGROUND: Alcohol-based hand rubs (ABHR) range in alcohol concentration from 60-95% and are available in a variety of delivery formats, such as rinses, gels, and foams. Recent studies suggest that some ABHR foams dry too slowly, thereby encouraging the use of inadequate volumes. This study investigates the influence of product volume, delivery format, and alcohol concentration on dry-time and antimicrobial efficacy of ABHR foams, gels and rinses. METHODS: ABHR dry-times were measured using volunteers to determine the influences of product volume, delivery format, and alcohol concentration. ABHR efficacies were evaluated according to the European Standard for Hygienic Hand Disinfection (EN 1500) using 3-mL application volumes rubbed for 30 s, and additionally, using volumes of the products determined to rub dry in 30 s. RESULTS: Volumes of six ABHR determined to rub dry in 30 s ranged from 1.7 mL to 2.1 mL, and the rate of drying varied significantly between products. ABHR dry-times increased linearly with application volume and decreased linearly with increasing alcohol concentration, but were not significantly influenced by product format. An ABHR foam (70% EtOH), rinse (80% EtOH), and gel (90% EtOH) each met EN 1500 efficacy requirements when tested at a volume of 3 mL, but failed when tested at volumes that dried in 30 s. CONCLUSIONS: Application volume is the primary driver of ABHR dry-time and efficacy, whereas delivery format does not significantly influence either. Although products with greater alcohol concentration dry more quickly, volumes required to meet EN 1500 can take longer than 30 s to dry, even when alcohol concentration is as high as 90%. Future studies are needed to better understand application volumes actually used by healthcare workers in practice, and to understand the clinical efficacy of ABHR at such volumes.

Efficacy of novel alcohol-based hand rub products at typical in-use volumes.

In vivo efficacies of 2 alcohol-based hand rub (ABHR) products (gel and foam) were evaluated at a volume of 1.1 mL. Both met US Food and Drug Administration log(10) reduction requirements after a single application and 10 consecutive applications. This is the first study to identify ABHR formulations capable of meeting efficacy requirements with a single-dispenser actuation.

Effectiveness of hand hygiene for removal of Clostridium difficile spores from hands.

This study determined whether surrogate organisms can predict activity against Clostridium difficile spores and compared the efficacy of hand hygiene preparations against C. difficile. Our data suggest that surrogate organisms were not predictive of C. difficile spore removal. Four preparations were significantly more effective than tap water at removing C. difficile.

Effectiveness of a comprehensive hand hygiene program for reduction of infection rates in a long-term care facility.

BACKGROUND: Alcohol-based hand rubs play a key role in reducing the transmission of pathogens in acute care settings, especially as part of a comprehensive hand hygiene program. However, their use in long-term care facilities (LTCFs) has been virtually unstudied. METHODS: Infection data, including those meeting McGeer et al and the Pennsylvania Patient Safety Authority's surveillance definitions, for lower respiratory tract infections (LRTIs) and skin and soft-tissue infections (SSTIs), as well as hospitalization data were collected in a 174-bed LTCF for 22 months (May 2009 to February 2011). In March 2010, a comprehensive hand hygiene program including increased product availability, education for health care personnel (HCP) and residents, and an observation tool to monitor compliance, was implemented. RESULTS: Infection rates for LRTIs were reduced from 0.97 to 0.53 infections per 1,000 resident-days (P = .01) following the intervention, a statistically significant decline. Infection rates for SSTIs were reduced from 0.30 to 0.25 infections per 1,000 resident-days (P = .65). A 54% compliance rate was observed among HCP. CONCLUSION: This study demonstrates that the use of alcohol-based hand rubs, as part of a comprehensive hand hygiene program for HCP and residents, can decrease infection rates in LTCFs.

Hand hygiene regimens for the reduction of risk in food service environments.

Pathogenic strains of Escherichia coli and human norovirus are the main etiologic agents of foodborne illness resulting from inadequate hand hygiene practices by food service workers. This study was conducted to evaluate the antibacterial and antiviral efficacy of various hand hygiene product regimens under different soil conditions representative of those in food service settings and assess the impact of product formulation on this efficacy. On hands contaminated with chicken broth containing E. coli, representing a moderate soil load, a regimen combining an antimicrobial hand washing product with a 70% ethanol advanced formula (EtOH AF) gel achieved a 5.22-log reduction, whereas a nonantimicrobial hand washing product alone achieved a 3.10log reduction. When hands were heavily soiled from handling ground beef containing E. coli, a wash-sanitize regimen with a 0.5% chloroxylenol antimicrobial hand washing product and the 70% EtOH AF gel achieved a 4.60-log reduction, whereas a wash-sanitize regimen with a 62% EtOH foam achieved a 4.11-log reduction. Sanitizing with the 70% EtOH AF gel alone was more effective than hand washing with a nonantimicrobial product for reducing murine norovirus (MNV), a surrogate for human norovirus, with 2.60- and 1.79-log reductions, respectively. When combined with hand washing, the 70% EtOH AF gel produced a 3.19-log reduction against MNV. A regimen using the SaniTwice protocol with the 70% EtOH AF gel produced a 4.04-log reduction against MNV. These data suggest that although the process of hand washing helped to remove pathogens from the hands, use of a wash-sanitize regimen was even more effective for reducing organisms. Use of a high-efficacy sanitizer as part of a wash-sanitize regimen further increased the efficacy of the regimen. The use of a well-formulated alcohol-based hand rub as part of a wash-sanitize regimen should be considered as a means to reduce risk of infection transmission in food service facilities.

Comparative efficacy of commercially available alcohol-based hand rubs and World Health Organization-recommended hand rubs: formulation matters.

BACKGROUND: Use of alcohol-based hand rubs (ABHRs) effectively reduces transmission of pathogenic microorganisms. However, the impact of alcohol concentration and format on product efficacy is currently being debated. METHODS: Two novel ABHR formulations containing 70% ethanol were evaluated according to American Society for Testing and Materials E1174 (Health Care Personnel Handwash [HCPHW]) and European Norm (EN) 1500 global standards. Additionally, using E1174, the efficacy of these formulations was compared head-to-head against 7 representative commercially available ABHRs and 2 World Health Organization recommended formulations containing alcohol concentrations of 60% to 90%. RESULTS: The novel ABHR formulations met efficacy requirements for both HCPHW and EN 1500 when tested at application volumes typically used in these methods. Moreover, these formulations met HCPHW requirements when tested at a more realistic 2-mL product application. In contrast, the commercial ABHRs and World Health Organization formulations failed to meet HCPHW requirements using a 2-mL application. Importantly, product performance did not correlate with alcohol concentration. CONCLUSION: Product formulation can greatly influence the overall antimicrobial efficacy of ABHRs and is a more important factor than alcohol concentration alone. Two novel ABHRs based on 70% ethanol have been formulated to meet global efficacy standards when tested at volumes more representative of normal product use in health care environments.

Quest for a realistic in vivo test method for antimicrobial hand-rub agents: introduction of a low-volume hand contamination procedure.

A novel method has been developed for the evaluation of alcohol-based hand rubs (ABHR) that employs a hand contamination procedure that more closely simulates the in-use conditions of ABHR. Hands of human subjects were contaminated with 0.2 ml of a concentrated suspension of Serratia marcescens (ATCC 14756) to achieve baseline contamination between 8 and 9 log10 CFU/hand while allowing product to be applied to dry hands with minimal soil load. Evaluation of 1.5 ml of an ABHR gel containing 62% ethanol produced log10 reductions of 2.66 ± 0.96, 2.40 ± 0.50, 2.41 ± 0.61, and 2.33 ± 0.49 (means ± standard deviations) after 1, 3, 7, and 10 successive contamination/product application cycles. In a study comparing this low-volume contamination (LVC) method to ASTM E1174, product dry times were more realistic and log10 reductions achieved by the ABHR were significantly greater when LVC was employed (P < 0.05). These results indicate that a novel low-volume hand contamination procedure, which more closely represents ABHR use conditions, provides more realistic estimates of in-use ABHR efficacies. Based on the LVC method, log10 reductions produced by ABHR were strongly dependent on the test product application volume (P < 0.0001) but were not influenced by the alcohol concentration when it was within the range of 62 to 85% (P = 0.378).

SaniTwice: a novel approach to hand hygiene for reducing bacterial contamination on hands when soap and water are unavailable.

The risk of inadequate hand hygiene in food handling settings is exacerbated when water is limited or unavailable, thereby making washing with soap and water difficult. The SaniTwice method involves application of excess alcohol-based hand sanitizer (ABHS), hand "washing" for 15 s, and thorough cleaning with paper towels while hands are still wet, followed by a standard application of ABHS. This study investigated the effectiveness of the SaniTwice methodology as an alternative to hand washing for cleaning and removal of microorganisms. On hands moderately soiled with beef broth containing Escherichia coli (ATCC 11229), washing with a nonantimicrobial hand washing product achieved a 2.86 (±0.64)-log reduction in microbial contamination compared with the baseline, whereas the SaniTwice method with 62 % ethanol (EtOH) gel, 62 % EtOH foam, and 70 % EtOH advanced formula gel achieved reductions of 2.64 ± 0.89, 3.64 ± 0.57, and 4.61 ± 0.33 log units, respectively. When hands were heavily soiled from handling raw hamburger containing E. coli, washing with nonantimicrobial hand washing product and antimicrobial hand washing product achieved reductions of 2.65 ± 0.33 and 2.69 ± 0.32 log units, respectively, whereas SaniTwice with 62 % EtOH foam, 70 % EtOH gel, and 70 % EtOH advanced formula gel achieved reductions of 2.87 ± 0.42, 2.99 ± 0.51, and 3.92 ± 0.65 log units, respectively. These results clearly demonstrate that the in vivo antibacterial efficacy of the SaniTwice regimen with various ABHS is equivalent to or exceeds that of the standard hand washing approach as specified in the U.S. Food and Drug Administration Food Code. Implementation of the SaniTwice regimen in food handling settings with limited water availability should significantly reduce the risk of foodborne infections resulting from inadequate hand hygiene.