By Judith Green-McKenzie, M.D., MPH, FACOEM, FACP, Garson Caruso, M.D., MPH · April 2006
New strategies for improving hand hygiene practices aim to reduce transmission of pathogens to patients and personnel in health care settings.
HOSPITAL-acquired (nosocomial) infections are estimated to occur in nearly 10 percent of all acute care hospitalizations. The estimated incidence is more than 2 million cases per year, resulting in an added expenditure in excess of $4.5 billion.
Transmission of both normal and pathological microorganisms by the hands of health care workers (HCWs) is one of the main routes of infection spread. Skin microorganisms may be considered resident flora or transient flora.
Resident flora, attached to the deeper layers of the skin, are persistently found on the skin and of low pathogenicity. Transient flora, colonizing the superficial layers of the skin, are consistently present on the skin, have higher pathogenicity, and are responsible for most instances of nosocomial infection transmission. The skin functions to reduce water loss, protect against microorganisms and abrasive action, and provide a permeability barrier to the environment.
Although contaminated sources such as infected or draining wounds or wound dressings are of obvious concern, colonization of the hands of HCWs by transient flora from intact patient skin is also common. Normal skin sheds approximately a million cells containing viable microorganisms daily, allowing contamination of objects in a patient's immediate environment, including gowns, bed linen, and furniture. Thus, HCWs can acquire transient organisms from apparently innocuous patient care activities.
The role of infectious agents' transmission by the hands of HCWs was independently recognized in the mid-19th century by Semmelweis in Austria, Holmes in the United States, and Lister in Scotland. Since that time, hand washing with soap and water or other disinfectant agents has become a standard practice for infection control in health care settings.
Hand washing with an antiseptic agent (an antimicrobial substance applied to skin to reduce the number of microbial flora) has long been considered effective in reducing the incidence of health care-associated infection. Compounds currently used for both routine and pre-surgical preparation hand antisepsis in health care settings include plain (non-antimicrobial) soap, chlorhexidine, chloroxylenol, hexachlorophene, quaternary ammonium compounds, and triclosan. Optimal hand hygiene should balance protecting the skin and resident flora, and reducing or eliminating transient flora. HCW compliance with recommended hand washing practices has been found to be low, with physicians being the least compliant.
Lack of appreciation of the potential for pathogenic contamination during routine patient care activities appears to be one factor in non-compliance. Comfort factors, such as development of skin irritation manifested as irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) due to repeated use of soaps, detergents, or antiseptic compounds, is another perceived barrier. HCWs' ability to tolerate available products (soap or other antimicrobial compounds) and acceptability of the product also may affect compliance. As frequent hand washing increases skin pH (decreases acidity), removes fatty acids (defatting), and reduces the barrier function of intact skin, reduction in normal skin antibacterial properties may result. Damaged skin harbors more pathogens, and washing damaged skin is less effective in reducing microorganism counts than washing intact skin. With continued patient care, microorganisms accumulate on the hands of HCWs over time.
Compliance may depend on convenience factors, including the degree of accessibility and the hand-washing or cleansing facilities' ease of use. In addition, HCWs who perceive time pressure as a result of workload, understaffing, and patient care demands may prioritize other patient-care activities over hand hygiene. Finally, cognitive factors such as lack of knowledge of hand hygiene guidelines or of scientific information regarding effectiveness, assumption of adequate protection from glove use, or simply forgetting contribute to non-compliance.
Alcohol-containing, waterless antiseptic agents applied to the hands are designed to reduce the number of viable microorganisms. Commonly used in Europe for many years, their use has lately become more widespread in the United States. In 1985, the Centers for Disease Control and Prevention recognized a limited role for alcohol-based hand antiseptics. Guidelines promulgated by the Association for Professionals in Infection Control (1995) expanded the role of these antiseptics, and recommendations were further expanded by CDC's Healthcare Infection Control Practices Advisory Committee (1996). More recently, CDC released a comprehensive guideline (2002) consolidating previous work recommending routine use of alcohol-based hand antiseptics in health care settings.
The effectiveness of alcohol as a germicide has been recognized for decades, and both alcohol and alcohol-based compounds have been used as antiseptics. Alcohol-based hand antiseptics available in the United States generally contain isopropanol (isopropyl alcohol), ethanol (ethyl alcohol), or a combination and are available as foams, gels, and rinses. The antimicrobial activity of the alcohols relates to their ability to denature (break down) proteins. Most effective in concentrations of 60 percent to 95 percent, alcohols are generally effective against fungi, Mycobacterium species (the causative agent of tuberculosis), some viruses (particularly those with outer envelopes containing lipids such as human influenza, herpes simplex, and human immunodeficiency viruses), and vegetative bacteria (including multi-drug resistant bacteria such as methcillin-resistant Staphylococcus aureus and vancomycin-resistant enterococcus). Neither isopropanol nor ethanol is effective against viruses without outer envelopes, bacterial spores, and protozoan oocysts. The effectiveness of alcohol-based hand hygiene preparations is affected by concentration, type, volume of alcohol used, contact time, and whether the hands are wet when these are applied.
An advantage of alcohol-based antiseptics is that their routine use has been associated with reduced nosocomial infection rates. They also require less time than traditional hand washing and irritate the hands less often. Hypersensitivity reactions, including ACD and contact urticaria, are rare with these agents. ICD incidence may be due to pre-existing skin damage from conventional hand washing and not to an irritant effect of the alcohol-containing antiseptic. Recontamination rates are reduced as the use of sinks, faucets, faucet handles, soaps and dispensers, and towels necessary for hand-washing is eliminated. In addition, microbial resistance is not considered problematic, possibly because of the mechanism of action (protein denaturation), rapid killing effect, or avoidance of subinhibitory alcohol concentrations due to rapid evaporation of the agent.
One disadvantage is that alcohol preparations are not effective against spore-forming bacteria such as Clostridium species or Bacillus anthracis, although adding 1 percent hydrogen peroxide may improve activity against the spores. Also, alcohol-based antiseptics are not recommended for use when hands are visibly soiled with dirt or debris or contaminated with organic biological materials. The drying effect of alcohol on the skin, another disadvantage, may be countered by the inclusion of emollients, humectants (moisture-retention agents), or other skin-conditioning agents. Preparations with strong fragrances may be poorly tolerated by HCWs with respiratory allergies or reactive airway conditions.
Alcohol-based antiseptics are potentially flammable, theoretically presenting both institutional and personal hazards. This institutional concern was recently addressed by the International Code Council in its adoption of rules (within the International Fire Code) allowing maximum access to alcohol-based hand antiseptics by end users, particularly in hospital corridors; this follows adoption of an amendment by the National Fire Protection Association permitting installation of dispensers in egress corridors. Finally, these preparations do not have persistent (residual) activity unless combined with other compounds, such as chlorhexidine, quaternary ammonium compounds, or triclosan.
In an effort to improve hand hygiene practices of HCWs and to reduce transmission of pathogenic microorganisms to patients and personnel in health care settings, the CDC helped develop and sponsored a guideline to promote new strategies for improving hand hygiene practices, which replace and update previous guidelines.
The guidelines strongly recommend hand washing when hands are visibly dirty, contaminated with proteinaceous material, or soiled with blood or other body fluid. However, they also strongly recommend that an alcohol-based hand rub be used (or, alternatively, that hands be washed with antimicrobial soap and water) for routine decontamination if hands are not visibly soiled, prior to direct patient contact, prior to donning sterile gloves, prior to inserting invasive devices such as catheters, after contact with body fluids, if moving from a contaminated-body site to a clean-body site, and after contact with inanimate objects. An alcohol-based hand rub with persistent activity is recommended before donning sterile gloves when performing surgical procedures, following manufacturer's instructions and allowing hands and forearms to dry prior to donning the gloves.
The guidelines also recommend that, in selecting hand hygiene products, personnel should be provided efficacious products with low irritancy potential, especially if the product is to be used multiple times per shift, and that HCWs be provided hand lotions or creams to minimize ICD associated with antisepsis. In addition, the guidelines recommend educating HCWs regarding the types of patient-care activities that can result in hand contamination and the advantages and disadvantages of various hand decontamination methods.
Alcohol-based hand rubs are now recommended for use in U.S. health care facilities. Availability and increased use can be facilitated by placing dispensers in convenient locations inside or outside patient rooms, and small bottled supplies can be carried by HCWs. Emollients can be added to improve acceptability. Proper and consistent use by HCWs should reduce the incidence of nosocomial infections in health care settings.
This article appeared in the April 2006 issue of Occupational Health & Safety.
Judith Green-McKenzie, M.D., MPH, FACOEM, FACP, is an assistant professor in the Division of Occupational Medicine, Department of Emergency Medicine, at the University of Pennsylvania School of Medicine.
Garson Caruso, M.D., MPH, is associate medical director at Bechtel Aberdeen Chemical Demilitarization Facility, Aberdeen Proving Ground-Edgewood Area, Md.
By Judith Green-McKenzie, M.D., MPH, FACOEM, FACP, Garson Caruso, M.D., MPH · April 2006