Even before Joseph Lister recommended that surgeons apply carbolic acid to their hands prior to procedures, physicians were aware that cleansing hands with an antiseptic agent could help control the spread of disease.
Even before Joseph Lister recommended that surgeons apply carbolic acid to their hands prior to procedures, physicians were aware that cleansing hands with an antiseptic agent could help control the spread of disease. In 1847, Ignaz Semmelweis successfully reduced the high rate of puerperal fever and maternal mortality at the General Hospital of Vienna by insisting that in addition to washing with soap and water, physicians clean their hands with a chlorine solution between patients.
Studies continue to demonstrate that improved hand hygiene can terminate disease outbreaks in health care facilities, reduce transmission of antimicrobial-resistant organisms, and reduce overall infection rates. Recently, the CDC issued new guidelines for hand hygiene in health care settings.1 The major change from earlier guidelines is the recommendation that health care workers use alcohol-based agents to routinely decontaminate hands that are not visibly soiled. Recent studies have shown that alcohol-based hand rubs significantly reduce the number of microorganisms on skin, are fast-acting, and cause less skin irritation than other forms of antisepsis.1
EFFECTIVENESS OF HAND HYGIENE PREPARATIONS
Agents currently used for hand hygiene in health care settings include plain soap, alcohol, chlorhexidine, chloroxylenol (PCMX), iodophors, quaternary ammonium compounds, and triclosan. These agents vary considerably in their effectiveness, rapidity of action, and capacity for persistent activity against common pathogens (Table).
Soap. Plain (nonantimicrobial) soap has little, if any, antimicrobial activity. In fact, hand washing with plain soap can result in an increase in the number of bacteria on the skin.2-5 However, when hands are visibly soiled, it is still necessary to wash them with soap and water.
Alcohols. Alcohols have excellent in vitro germicidal activity against gram-positive and gram-negative bacteria (including multidrug- resistant pathogens), mycobacteria, various fungi, and a number of enveloped viruses. They are more effective for standard hand antisepsis than plain soap or antimicrobial soaps. Moreover, alcohols are rapidly germicidal when applied to the skin. The efficacy of alcohol-based products is affected by several factors, including the type of alcohol used, concentration, contact time, and volume of alcohol used. Hand antisepsis with a small volume of alcohol is no more effective than hand washing with plain soap and water.6,7
One drawback to alcohol-based products is that they have only minimal persistent (ie, residual) activity. However, the addition of chlorhexidine, quaternary ammonium compounds, octenidine, or triclosan to alcohol-based solutions can give these products persistent activity.
Antimicrobial agents in hand washes. Chlorhexidine has good in vitro activity against gram-positive bacteria and enveloped viruses, less activity against gram-negative bacteria and fungi, and only minimal activity against tubercle bacilli. Chlorhexidine acts more slowly than alcohols but has substantial residual activity.
Iodine and iodophors have activity against gram-positive and gram-negative bacteria, mycobacteria, viruses, and fungi. The extent of their persistent antimicrobial activity is not clear.
Triclosan, like chlorhexidine, has a broad range of antimicrobial activity and has persistent activity on the skin. PCMX is slower-acting than chlorhexidine or iodophors and has less residual activity than chlorhexidine. Quaternary ammonium compounds inhibit the growth of bacteria and fungi but have relatively weak microbiocidal activity. In addition, the presence of organic material adversely affects their activity. The FDA is still evaluating the safety and efficacy of triclosan, PCMX, and quaternary ammonium compounds.
ACCEPTANCE OF HAND HYGIENE PRODUCTS
To be effective, hand hygiene products must not only possess antimicrobial properties against a range of pathogens, they must also be acceptable to the health care providers who use them. Product characteristics that can affect acceptance include drying effects, allergenicity, ease of use, fragrance, consistency, and even color.
Drying effects and allergenicity. Health care workers may wash their hands as many as 30 times per shift, and repeated use of hand hygiene products is a primary cause of chronic irritant contact dermatitis. The degree of skin irritation and dryness produced by a given product significantly influences acceptance and ultimate use. Soaps and detergents are particularly irritating and drying. Iodophors cause more irritant contact dermatitis than other antiseptics commonly used for hand hygiene. Alcohol-based products are the least drying or irritating. Allergic reactions have been reported with all types of antiseptic agents; however, allergic contact dermatitis associated with alcohol-based hand rubs is rare.
Ease of use. Another factor likely to significantly influence the acceptance of alcohol-based hand rubs is their ease and speed of use. In an 8-hour shift in an ICU, nurses would spend 1 hour less time on hand hygiene if they used an alcohol-based rub rather than soap and water.8 Moreover, because alcohol-based hand rubs are not used with running water, dispensers can be installed in convenient locations or carried by health care workers in a pocket.
Other factors that affect acceptance. Drawbacks to some alcohol-based hand gels include the sensation of an unpleasant "buildup" of emollients on the hands after repeated use. To counter this effect, some manufacturers recommend washing hands with soap and water after 5 to 10 applications of a gel. Also, certain alcohol-based hand rubs may interact with the powder that remains on the hands after the use of powdered gloves, producing a gritty feeling.
OTHER PRACTICES THAT AFFECT HAND HYGIENE
Gloves. Wearing gloves can help reduce the transmission of pathogens in health care settings. However, gloves do not provide complete protection against hand contamination. Health care workers should wash their hands or decontaminate them after removing gloves. Other recommendations include:
Fingernails. Studies have shown that high concentrations of bacteria are found on subungual skin.9,10 It is recommended that health care workers who have direct contact with patients at high risk not wear artificial fingernails or extenders. Natural nail tips should be trimmed to less than 1/4 inch.
Jewelry. Several studies have shown that more bacteria are found on the skin under rings than elsewhere on the hand.11-13 However, it is still unclear whether the wearing of rings results in greater transmission of pathogens. The CDC currently makes no recommendation regarding the wearing of rings in health care settings.
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2. Larson E, Leyden JJ, McGinley KJ, et al. Physiologic and microbiologic changes in skin related to frequent handwashing. Infect Control. 1986;7:59-63.
3. Meers PD, Yeo GA. Shedding of bacteria and skin squames after handwashing. J Hyg(Lond). 1978;81:99-105.
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5. Maki DG, Zilz MA, Alvarado CJ. Evaluation of the antibacterial efficacy of four agents for handwashing. In: Nelson JC, Grassi C, eds. Current Chemotherapy and Infectious Disease Proceedings of the 11th International Congress on Chemotherapy and the 19th ICACC. Washington, DC: American Society for Microbiology; 1979.
6. Marples RR, Towers AG. A laboratory model for the investigation of contact transfer of micro-organisms. J Hyg(Lond). 1979;82:237-248.
7. Mackintosh CA, Hoffman PN. An extended model for transfer of micro-organisms via the hands: differences between organisms and the effect of alcohol disinfection. J Hyg(Lond). 1984;92:345-355.
8.Hand Hygiene Guidelines Fact Sheet. Atlanta: CDC Office of Communication; 2002.
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10. Hedderwick SA, McNeil SA, Lyons MJ, Kauffman CA. Pathogenic organisms associated with artificial fingernails worn by healthcare workers. Infect Control Hosp Epidemiol. 2000;21:505-509.
11. Aseptic methods in the operating suite. Lancet. 1968;1:705-709.
12. Hoffman PN, Cooke EM, McCarville MR, Emmerson AM. Micro-organisms isolated from skin under wedding rings worn by hospital staff. Br Med J (Clin Res Ed). 1985;290:206-207.
13. Jacobson G, Thiele JE, McCune JH, Farrell LD. Handwashing: ring-wearing and number of microorganisms. Nurs Res. 1985;34:186-188.