When soap and water not available, consider alcohol gels

Proper technique, including volume and duration of use with hand rubbing, is very important and should be stressed when using soap and alcohol-based products.

With the respiratory and influenza seasons upon us, limiting and preventing respiratory tract infection is a goal the public and health care workers share.

As hand washing is the single most effective strategy to limit spread of infectious microorganisms, hand disinfecting stations and alcohol gel dispensing containers are frequently encountered in public and commercial establishments, as well as in health care institutions. A stroll through a grocery store or pharmacy will reveal numerous brands of antimicrobial soaps and alcohol-based disinfecting products in various forms, including liquids, gels, wipes and sprays. This month’s column will review the efficacy and role of these products.

Soaps

Soaps have detergent properties that remove dirt and various organic substances from hands. Although plain soaps do not have appreciable antimicrobial activity, hand washing with plain soap for 15 seconds reduces bacterial counts by approximately 1 log10, and washing for 30 seconds reduces bacterial counts by up to 2.8 log10. In 2002, the CDC published guidelines on hand hygiene in health care settings. Soap (plain or antimicrobial soap) is recommended for hand washing when hands are visibly dirty or soiled with bodily fluids.

If hands are not visibly soiled, use of an alcohol-based hand rub is acceptable for routine decontamination of hands. Recommendations from the CDC on hand washing in the home and outside of health care institutions include use of soap and water and alcohol-based hand rubs when soap and water are not available. Information on hand hygiene from the AAP states that antimicrobial soaps are no more effective at cleansing hands than plan soaps and antimicrobial soaps are not recommended.

Many soap products found on store shelves are advertised as “antibacterial” soaps.

The most common antibacterial agent in these soaps is triclosan. Triclosan has been available for commercial use for 40 years, and within the past 10 years, it has been incorporated into numerous soap products for consumer use. Triclosan has activity against many gram-positive bacteria, but it is less active against gram-negative bacteria. Some reports of contamination with gram-negative bacteria have occurred. The FDA has classified triclosan in concentrations of 1%, as insufficient data exist to classify it as safe and effective as an antiseptic handwash. Soap products containing triclosan typically include it in a concentration of 0.1%-0.45%. Environmental groups and others have raised concerns about triclosan. Triclosan can be degraded by ultraviolet sunlight to dioxin, a known toxic substance.

The authors of a literature review of published community setting studies of antibacterial soaps conducted from 1980-2006 concluded that antibacterial soaps are no more effective than plain soap in preventing infection (ie, respiratory or gastrointestinal) or reducing hand bacterial levels (Aiello). Studies were included in this review if they evaluated cross-resistance mechanisms or assessed efficacy at reducing infection or hand bacterial levels in community settings. The effectiveness of antibacterial soaps containing triclosan at concentrations found in currently available products was no greater than plain soaps in most studies. Soaps containing higher concentrations of triclosan (greater than 1%), and when used for longer (30 seconds) or multiple hand washings, demonstrated an increased ability to decrease hand bacterial levels over plain soap. Concerns were raised in several studies of triclosan-adapted cross-resistance to various antibiotics by several species of bacteria. More research on the potential for cross-resistance is necessary before more definitive conclusions can be made about cross-resistance. In 2005, an FDA advisory panel concluded that antibacterial soaps are no more effective than plain soaps.

Whether plain soap or antibacterial soaps are used, it is likely that many consumers, and even health care workers, do not use them properly. Several studies have shown that the longer hands are washed with soap, the more efficacious they are to reduce bacterial levels. The CDC recommends hand washing vigorously with soap and water for 20 seconds, covering all surfaces of the hands and fingers. Alternatively, one could sing “Happy Birthday to You” two times, which should require approximately 20 seconds. A common concern with use of soaps is their drying effect on skin. Many soap products contain emollients to reduce skin drying and irritation. The CDC recommends that health care workers be provided with hand lotions or creams to reduce skin irritation from frequent hand washing.

Alcohol-based products

Many antimicrobial products available to consumers are alcohol-based (commonly containing ethyl alcohol). These products are most familiar to consumers as gels, although rinses, wipes and, most recently sprays, are also marketed.

The CDC recommends use of alcohol-based hand rubs when soap and water are not available, or alcohol-based products can be used when hands are not visibly soiled. Similarly, the AAP recommends use of alcohol-based products when soap and water are not available.

Most alcohol-based products contain ethyl alcohol in a concentration of 60% to 95%, and it is these concentrations that are most effective. Alcohols function to denature proteins of microorganisms. Alcohol has excellent antimicrobial activity against many gram-positive and gram-negative bacteria, including some multidrug resistant pathogens, such as methicillin-resistant Staphylococcus aureus, some fungi and some enveloped viruses, including herpes simplex, HIV, influenza and RSV.

The FDA classifies ethyl alcohol (60% to 95%) as generally safe and effective for use in antiseptic handwash products. In studies comparing standard hand washing with alcohol-based products to plain soap or antimicrobial soap in health care workers, use of alcohol-based products was more effective at reducing hand bacterial levels. In an observational, prospective cohort study evaluating transmission of respiratory and gastrointestinal illnesses in families with children aged 6 months to 5 years enrolled in child care, Lee found reduced transmission of respiratory illness among families reporting frequent use of alcohol gels.

Proper technique of use is also important when using alcohol-based products. The most effective volume of liquid products to use is not known. Small volumes (less than 1 mL) have limited, if any, efficacy. A volume of 1 mL was shown to be less effective than 3 mL in one study. Enough of the product should be applied to the hands to keep them feeling moist for 10 to 15 seconds of rubbing together. Products may or may not specify what volume to use in their labeling. Many alcohol-based products contain emollients to reduce skin irritation from the drying effects of alcohol.

As alcohol-based products contain a substantial amount of alcohol, they should be used cautiously around children. Reports of intentional ingestion and intoxication by adults and children have occurred in the lay and medical literature. A single lick to the hand by a child using an alcohol-based product is unlikely to cause toxicity, other than irritating the mouth or tongue. However, if a 27-pound, 2-year-old child ingests a 2-ounce bottle of an alcohol-based product (typical size sold), it is possible that a blood ethyl alcohol level of 445 mg/dL could result (compared with 80 mg/dL as legally drunk in many states). A single swallow could result in a blood ethyl alcohol level of 50 mg/dL, which could produce signs and symptoms of toxicity.

Some antimicrobial hand hygiene products are not alcohol-based but contain benzalkonium chloride. The FDA said there are insufficient data to classify benzalkonium chloride as safe and effective. Products containing benzalkonium chloride should not be used.

Conclusions

Soap and water use is an effective method of proper hand hygiene for children and the community, and is recommended by the CDC and the AAP. Antimicrobial soaps, which are commonly sold and advertised, have not been shown to be more effective than plain soaps in reducing hand bacterial levels or reducing infection.

When soap and water are not available, or for convenience, alcohol-based antimicrobial hand products, such as gels, are effective and are recommended for use. As these products contain alcohol, however, they should be used and stored safely with children.

Proper technique, including volume and duration of use with hand rubbing, is very important and should be stressed when using soap and alcohol-based products.

For more information:

• Aiello AE. Consumer antibacterial soaps: effective or just risky? Clin Infect Dis. 2007;45(Suppl 2):S137-47.
• CDC. Guideline for hand hygiene in health-care settings. MMWR. 2002;51:1-56.
• Children and ethanol-based hand sanitizers. Iowa Statewide Poison Control Center. 2007; www.extension/iastate.edu/foodsafety/Hand%20Sanitizers.pdf.
• Lee GM. Illness transmission in the home: a possible role for alcohol-based hand gels. Pediatrics. 2005;115:852-60.

Edward A. Bell, PharmD, is a Professor of Clinical Sciences at Drake University College of Pharmacy, Blank Children’s Hospital and Clinics in Des Moines, Iowa.