11.1. Water
The purpose of routine handwashing in patient care is to remove dirt and organic material as well as microbial contamination acquired by contact with patients or the environment.
While water is often called a “universal solvent”, it cannot directly remove hydrophobic substances such as fats and oils often present on soiled hands. Proper handwashing therefore requires the use of soaps or detergents to dissolve fatty materials and facilitate their subsequent flushing with water. To ensure proper hand hygiene, soap or detergent must be rubbed on all surfaces of both hands followed by thorough rinsing and drying. Thus, water alone is not suitable for cleaning soiled hands; soap or detergent must be applied as well as water.
11.1.1. Association of water contamination with infections
Tap water may contain a variety of microorganisms including human pathogens. and list known or suspected waterborne pathogens, together with their health significance, stability in water, and relative infectivity.228
Examples of common water contaminants and their effects.
Waterborne pathogens and their significance in water supplies.
11.1.2. Microbially-contaminated tap water in health-care institutions
Tap water in health-care institutions can be a source of nosocomial infections. A Medline search from 1966 to 2001 found 43 such outbreaks, of which 69% (29) could be linked by epidemiological and molecular evidence to biofilms (a community of microorganisms growing as a slimy layer on surfaces immersed in a liquid) in water storage tanks, tap water, and water from showers.229–232 Pathogens identified in waterborne nosocomial infections include: Legionella spp., P. aeruginosa,233,234Stenotrophomonas maltophilia,235Mycobacterium avium,236M. fortuitum,237M. chelonae,238Fusarium spp.,239 and A. fumigatus.240 Even if hand hygiene practices are in place, a plausible route for transmitting these organisms from water to patient could be through HCWs’ hands if contaminated water is used to wash them. WHO has developed a reference document on Legionella spp. and the prevention of legionellosis which provides a comprehensive overview of the sources, ecology, and laboratory detection of this microorganism.241 It should be noted, however, that Legionella spp. are transmitted primarily through inhalation of aerosolized or aspirated water.
A Norwegian study to determine the occurrence, distribution, and significance of mould species in drinking-water found 94 mould species belonging to 30 genera, including Penicillium, Trichoderma, and Aspergillus spp. Of these, Penicillium spp. were abundantly distributed and appeared to survive water treatment. Although heating of water reduced the levels of fungal contamination, A. ustus appeared to be somewhat resistant to such treatment. Potentially pathogenic species of fungi in tap water may be particularly important in settings where immunocompromised patients are housed.242
11.1.3. Tap water quality
Tap water, in addition to being a possible source of microbial contamination, may include substances that may interfere with the microbicidal activities of antiseptics and disinfectants. Examples of common water contaminants and their effects are summarized in .
The physical, chemical and microbiological characteristics of water to be used for handwashing in health-care institutions must meet local regulations.228 The institution is responsible for the quality of water once it enters the building. WHO has developed guidelines for essential environmental health standards in health care for developing countries.243 In Europe, the quality of drinkable water in public buildings is regulated by the European Council’s Directive “Water for Human Consumption” (Regulation 1882/2003/EC)244 (). In France, national guidelines for health-care settings have recently proposed microbiological standards for water quality ().
Microbiological indicators for drinking-water quality according to 1882/2003/EC.
Microbiological indicators for water quality in health-care settings in France.
If an institution’s water is suspected of being contaminated, it can be made microbiologically safer by filtration and/or disinfection.228 Disinfectants include chlorine, monochloramine, chlorine dioxide, ozone, and ultraviolet irradiation.228 Chlorine, in gas or liquid form, remains the most common chemical used for this purpose, but is prone to generating potentially toxic by-products in the treated water. Ozone has high installation costs; monochloramine, while being slower than chlorine in its microbicidal action, does leave a disinfectant residual and is also less likely to generate harmful by-products.
The first step of conventional water treatment is the removal of as much of the organic matter and particulates as possible through coagulation, sedimentation, and filtration. Water is then disinfected before entering the distribution system. It is highly desirable to maintain a disinfectant residual in the treated water while it is in transit, in order to limit the growth of microorganisms in the distribution system and to inactivate any pathogens that may enter the distribution system through cross-connections, leakage, seepage or backflow. However, conventional levels of disinfectant residuals may be ineffective against massive contamination influx.245
Ultraviolet radiation is a potential alternative to chemical disinfection of small water systems, as long as such water is free of suspended matter, turbidity, and colour. The main disadvantage is that ultraviolet treatment does not leave a disinfectant residual.246
In Japan, the regulation on water supply mandates the use of sterile water instead of tap water for preoperative scrubbing of hands. However, a Japanese study showed that bacterial counts on hands were essentially the same, irrespective of the type of water used, and emphasized the importance of maintaining a free chlorine residual of >0.1 ppm in tap water.247
In many developing countries, tap water may be unfit for drinking. While drinkable water may also be ideal for handwashing, available evidence does not support the need for potable water for washing hands. In a resource-limited area of rural Bangladesh,248 education and promotion of handwashing with plain soap and available water significantly reduced the spread of diarrhoeal diseases across all age groups.248 A similar study in Pakistan corroborated these findings.249
Nevertheless, if the water is considered potentially unsafe for handwashing, the use of antibacterial soap alone may not be adequate. Washed hands may require further decontamination with antiseptic handrubs, especially in areas with high-risk populations,250 while steps are initiated to improve water quality through better treatment and disinfection.
Health-care institutions in many parts of the developing world may not have piped-in tap water, or it may be available only intermittently. An intermittent water supply system often has higher levels of microbial contamination because of the seepage of contamination occurring while the pipes are supplied with treated water. On-site storage of sufficient water is often the only option in sites without a reliable supply. However, such water is known to be prone to microbial contamination unless stored and used properly and may require point-of-use treatment and/or on-site disinfection.251
Containers for on-site storage of water should be emptied and cleaned252 as frequently as possible and, when possible, inverted to dry. Putting hands and contaminated objects into stored water should be avoided at all times. Storage containers should ideally be narrow-necked to facilitate proper coverage, with a conveniently located tap/faucet for ease of water collection.
CDC has developed guidelines for safe water systems and hand hygiene in health care in developing countries,253 which were field-tested in Kenya and have been adapted to other countries in Africa and in Asia.254 According to the recommendations included in this document, drinkable water should be used for handwashing.
11.1.4. Water temperature
Apart from the issue of skin tolerance and level of comfort, water temperature does not appear to be a critical factor for microbial removal from hands being washed. In contrast, in a study comparing water temperatures of 4 °C, 20 °C and 40 °C, warmer temperatures have been shown to be very significantly associated with skin irritation.255 The use of very hot water for handwashing should therefore be avoided as it increases the likelihood of skin damage.
11.1.5. Hand drying
Because wet hands can more readily acquire and spread microorganisms, the proper drying of hands is an integral part of routine handwashing. Careful hand drying is a critical factor determining the level of bacterial transfer associated with touch-contact after hand cleansing. Care must also be taken to avoid recontamination of washed and dried hands.75 Recognition of this fact could significantly improve hand hygiene practices in clinical and public health sectors.75
Paper towels, cloth towels, and warm air dryers are commonly used to dry washed hands. One study compared four methods of hand drying: cloth towels from a roller; paper towels left on a sink; warm air dryer; and letting hands dry by evaporation;256 no significant difference in the efficacy of the methods was reported. Reusing or sharing towels should be avoided because of the risk of cross-infection.257 In a comparison of methods to test the efficiency of hand drying for the removal of bacteria from washed hands, warm air drying performed worse than drying with paper towels.258 This is in contrast to another study, which found warm air dryers to be the most efficient when compared with paper and cloth towels.257 However, air dryers may be less practical because of the longer time needed to achieve dry hands,258 with a possible negative impact on hand hygiene compliance. Furthermore, one study suggested that some air driers may lead to the aerosolization of waterborne pathogens.259 Further studies are needed to issue recommendations on this aspect. Ideally, hands should be dried using either individual paper towels or hand driers which can dry hands effectively and as quickly as it can be done with paper towels, and have been proven not to be associated with the aerosolization of pathogens.
When clean or disposable towels are used, it is important to pat the skin rather than rub it, to avoid cracking. Skin excoriation may lead to bacteria colonizing the skin and possible spread of bloodborne viruses as well as other microorganisms.79 Sore hands may also lead to decreased compliance with hand hygiene practices (see also Part I, Section 15).
11.2. Plain (non-antimicrobial) soap
Soaps are detergent-based products that contain esterified fatty acids and sodium or potassium hydroxide. They are available in various forms including bar soap, tissue, leaf, and liquid preparations. Their cleansing activity can be attributed to their detergent properties which result in the removal of lipid and adhering dirt, soil, and various organic substances from the hands. Plain soaps have minimal, if any, antimicrobial activity, though handwashing with plain soap can remove loosely adherent transient flora. For example, handwashing with plain soap and water for 15 seconds reduces bacterial counts on the skin by 0.6–1.1 log10, whereas washing for 30 seconds reduces counts by 1.8–2.8 log10.48 In several studies, however, handwashing with plain soap failed to remove pathogens from the hands of HCWs.88,110,260 Handwashing with plain soap can result in a paradoxical increase in bacterial counts on the skin.220,261–263 Because soaps may be associated with considerable skin irritation and dryness,220,262,264 adding humectants to soap preparations may reduce their propensity to cause irritation. Occasionally, plain soaps have become contaminated, which may lead to the colonization of HCWs hands with Gram-negative bacilli.160 Nevertheless, there is some evidence that the actual hazard of transmitting microorganisms through handwashing with previously used soap bars is negligible.265,266
11.3. Alcohols
Most alcohol-based hand antiseptics contain either ethanol, isopropanol or n-propanol, or a combination of two of these products. Concentrations are given as either percentage of volume (= ml/100 ml, abbreviated % v/v), percentage of weight (= g/100 g, abbreviated % m/m), or percentage of weight/volume (= g/100 ml, abbreviated % m/v). Studies of alcohols have evaluated either individual alcohols in varying concentrations (most studies), combinations of two alcohols, or alcohol solutions containing small amounts of hexachlorophene, quaternary ammonium compounds (QAC), povidone-iodine, triclosan or CHG.137,221,267–286
The antimicrobial activity of alcohols results from their ability to denature proteins.287 Alcohol solutions containing 60–80% alcohol are most effective, with higher concentrations being less potent.288,289 This paradox results from the fact that proteins are not denatured easily in the absence of water.287 The alcohol content of solutions may be expressed as a percentage by weight (m/m), which is not affected by temperature or other variables, or as a percentage by volume (v/v), which may be affected by temperature, specific gravity and reaction concentration.290 For example, 70% alcohol by weight is equivalent to 76.8% by volume if prepared at 15 °C, or 80.5% if prepared at 25 °C.290 Alcohol concentrations in antiseptic handrubs are often expressed as a percentage by volume.198
Alcohols have excellent in vitro germicidal activity against Gram-positive and Gram-negative vegetative bacteria (including multidrug-resistant pathogens such as MRSA and VRE), M. tuberculosis, and a variety of fungi.287–289,291–296 However, they have virtually no activity against bacterial spores or protozoan oocysts, and very poor activity against some non-enveloped (non-lipophilic) viruses. In tropical settings, the lack of activity against parasites is a matter of concern about the opportunity to promote the extensive use of alcohol-based handrubs, instead of handwashing, which may at least guarantee a mechanical removal effect.
Some enveloped (lipophilic) viruses such as herpes simplex virus (HSV), HIV, influenza virus, RSV, and vaccinia virus are susceptible to alcohols when tested in vitro ().297 Other enveloped viruses that are somewhat less susceptible, but are killed by 60–70% alcohol, include hepatitis B virus (HBV) and probably hepatitis C virus.298 In a porcine tissue carrier model used to study antiseptic activity, 70% ethanol and 70% isopropanol were found to reduce titres of an enveloped bacteriophage more effectively than an antimicrobial soap containing 4% CHG.192
Virucidal activity of antiseptic agents.
Numerous studies have documented the in vivo antimicrobial activity of alcohols. Early quantitative studies of the effects of antiseptic handrubs established that alcohols effectively reduce bacterial counts on hands.63,288,292,299 Typically, log reductions of the release of test bacteria from artificially contaminated hands average 3.5 log10 after a 30-second application, and 4.0–5.0 log10 after a 1-minute application.48 In 1994, the FDA TFM classified ethanol 60–95% as a generally safe and effective active agent for use in antiseptic hand hygiene or HCW handwash products.198 Although the TFM considered that there were insufficient data to classify isopropanol 70–91.3% as effective, 60% isopropanol has subsequently been adopted in Europe as the reference standard against which alcohol-based handrub products are compared201 (see Part I, Section 10.1.1). Although n-propanol is found in some hand sanitizers in Europe,300 it is not included by the TFM in the list of approved active agents for hand antisepsis and surgical hand preparation in the USA.58
Alcohols are rapidly germicidal when applied to the skin, but have no appreciable persistent (residual) activity. However, regrowth of bacteria on the skin occurs slowly after use of alcohol-based hand antiseptics, presumably because of the sub-lethal effect alcohols have on some of the skin bacteria.301,302 Addition of chlorhexidine, quaternary ammonium compounds, octenidine or triclosan to alcohol-based formulations can result in persistent activity.48 A synergistic combination of a humectant (octoxyglycerine) and preservatives has resulted in prolonged activity against transient pathogens.303 Nevertheless, a recent study on bacterial population kinetics on gloved hands following treatment with alcohol-based handrubs with and without supplements (either CHG or mecetronium etilsulfate) concluded that the contribution of supplements to the delay of bacterial regrowth on gloved hands appeared minor.227
Alcohols, when used in concentrations present in alcoholbased handrubs, also have in vivo activity against a number of non-enveloped viruses (). For example, in vivo studies using a fingerpad model have demonstrated that 70% isopropanol and 70% ethanol were more effective than medicated soap or non-medicated soap in reducing rotavirus titres on fingerpads.257,304 A more recent study using the same test methods evaluated a commercially available product containing 60% ethanol, and found that the product reduced the infectivity titres of three non-enveloped viruses (rotavirus, adenovirus, and rhinovirus) by 3 to 4 logs.305 Other non-enveloped viruses such as hepatitis A and enteroviruses (e.g. poliovirus) may require 70–80% alcohol to be reliably inactivated.306,307 It is worth noting that both 70% ethanol and a 62% ethanol foam product with humectants reduced hepatitis A virus titres on whole hands or fingertips to a greater degree than non-medicated soap, and both reduced viral counts on hands to about the same extent as antimicrobial soap containing 4% CHG.308 The same study found that both 70% ethanol and the 62% ethanol foam product demonstrated greater virucidal activity against poliovirus than either non-antimicrobial soap or a 4% CHG-containing soap.308 However, depending on the alcohol concentration, time, and viral variant, alcohol may not be effective against hepatitis A and other non-lipophilic viruses. Schurmann concluded that the inactivation of naked (nonenveloped) viruses is influenced by temperature, the ratio of disinfectant to virus volume, and protein load.309 Various 70% alcohol solutions (ethanol, n-propanol, isopropanol) were tested against a surrogate of norovirus and ethanol with 30-second exposure demonstrated virucidal activity superior to the others.310 In a recent experimental study, ethyl alcohol-based products showed significant reductions of the tested surrogate for a non-enveloped human virus; however, activity was not superior to non-antimicrobial or tap/faucet water controls311. In general, ethanol has greater activity against viruses than isopropanol70. Further in vitro and in vivo studies of both alcohol-based formulations and antimicrobial soaps are warranted to establish the minimal level of virucidal activity that is required to interrupt direct contact transmission of viruses in health-care settings.
Alcohols are not good cleansing agents and their use is not recommended when hands are dirty or visibly contaminated with proteinaceous materials. When relatively small amounts of proteinaceous material (e.g. blood) are present, however, ethanol and isopropanol may reduce viable bacterial counts on hands,312 but do not obviate the need for handwashing with water and soap whenever such contamination occurs.179 A few studies have examined the ability of alcohols to prevent the transfer of health care-associated pathogens by using experimental models of pathogen transmission.74,88,169 Ehrenkranz and colleagues88 found that Gram-negative bacilli were transferred from a colonized patient’s skin to a piece of catheter material via the hands of nurses in only 17% of experiments following antiseptic handrub with an alcohol-based hand rinse. In contrast, transfer of the organisms occurred in 92% of experiments following handwashing with plain soap and water. This experimental model suggests that when HCWs hands are heavily contaminated, alcohol-based handrubbing can prevent pathogen transmission more effectively than handwashing with plain soap and water.
summarizes a number of studies that have compared alcohol-based products with plain or antimicrobial soaps to determine which was more effective for standard handwashing or hand antisepsis by HCWs (for details see Part I, Section 11.13).88,125,137,221,223,273–279,286,313–321
Studies comparing the relative efficacy (based on log10 reductions achieved) of plain soap or antimicrobial soaps versus alcoholbased antiseptics in reducing counts of viable bacteria on hands.
The efficacy of alcohol-based hand hygiene products is affected by a number of factors including the type of alcohol used, concentration of alcohol, contact time, volume of alcohol used, and whether the hands are wet when the alcohol is applied. Small volumes (0.2–0.5 ml) of alcohol applied to the hands are no more effective than washing hands with plain soap and water.74,169 Larson and colleagues151 documented that 1 ml of alcohol was significantly less effective than 3 ml. The ideal volume of product to apply to the hands is not known and may vary for different formulations. In general, however, if hands feel dry after being rubbed together for less than 10–15 seconds, it is likely that an insufficient volume of product was applied. Alcohol-impregnated towelettes contain only a small amount of alcohol and are not much more effective than washing with soap and water.74,322,323
Alcohol-based handrubs intended for use in hospitals are available as solutions (with low viscosity), gels, and foams. Few data are available regarding the relative efficacy of various formulations. One small field trial found that an ethanol gel was somewhat less effective than a comparable ethanol solution at reducing bacterial counts on the hands of HCWs.324 Recent studies found similar results demonstrating that solutions reduced bacterial counts on the hands to a significantly greater extent than the tested gels.203,325 Most gels showed results closer to a 1-minute simple handwash than to a 1-minute reference antisepsis.296 New generations of gel formulations with higher antibacterial efficacy than previous products have since been proposed.70 Further studies are warranted to determine the relative efficacy of alcohol-based solutions and gels in reducing transmission of health care-associated pathogens. Furthermore, it is worth considering that compliance is probably of higher importance, thus if a gel with lower in vitro activity is more frequently used, the overall outcome is still expected to be better.
Frequent use of alcohol-based formulations for hand antsepsis tends to cause drying of the skin unless humectants or other skin conditioning agents are added to the formulations. For example, the drying effect of alcohol can be reduced or eliminated by adding 1–3% glycerol or other skin conditioning agents.219,221,267,268,273,301,313,326,327
Moreover, in prospective trials, alcohol-based solutions or gels containing humectants caused significantly less skin irritation and dryness than the soaps or antimicrobial detergents tested.262,264,328,329 These studies, which were conducted in clinical settings, used a variety of subjective and objective methods for assessing skin irritation and dryness. Further studies of this type are warranted to establish if products with different formulations yield similar results.
Even well-tolerated alcohol-based handrubs containing humectants may cause a transient stinging sensation at the site of any broken skin (cuts, abrasions). Alcohol-based handrub preparations with strong fragrances may be poorly tolerated by a few HCWs with respiratory allergies. Allergic contact dermatitis or contact urticaria syndrome caused by hypersensitivity to alcohol, or to various additives present in some alcohol-based handrubs, occurs rarely (see also Part I, Section 14).330–332
A systematic review of publications between 1992 and 2002 on the effectiveness of alcohol-based solutions for hand hygiene showed that alcohol-based handrubs remove organisms more effectively, require less time, and irritate skin less often than handwashing with soap or other antiseptic agents and water.333 The availability of bedside alcohol-based solutions increased compliance with hand hygiene among HCWs.60,333–335 Regarding surgical hand preparation, an alcohol-based waterless surgical scrub was shown to have the same efficacy and demonstrated greater acceptability and fewest adverse effects on skin compared with an alcohol-based water-aided solution and a brush-based iodine solution.336
Alcohols are flammable, and HCWs handling alcohol-based preparations should respect safety standards (see Part I, Section 23.6). Because alcohols are volatile, containers should be designed so that evaporation is minimized and initial concentration is preserved. Contamination of alcohol-based solutions has seldom been reported. One report documented a pseudo-epidemic of infections resulting from contamination of ethyl alcohol by Bacillus cereus spores337 and in-use contamination by Bacillus spp. has been reported.338
11.4. Chlorhexidine
CHG, a cationic bisbiguanide, was developed in the United Kingdom in the early 1950s and introduced into the USA in the 1970s.204,339 Chlorhexidine base is barely soluble in water, but the digluconate form is water-soluble. The antimicrobial activity of chlorhexidine appears to be attributable to the attachment to, and subsequent disruption of cytoplasmic membranes, resulting in precipitation of cellular contents.48,204 Chlorhexidine’s immediate antimicrobial activity is slower than that of alcohols. It has good activity against Gram-positive bacteria, somewhat less activity against Gram-negative bacteria and fungi, and minimal activity against mycobacteria.48,204,339 Chlorhexidine is not sporicidal.48,339. It has in vitro activity against enveloped viruses such as herpes simplex virus, HIV, cytomegalovirus, influenza, and RSV, but significantly less activity against non-enveloped viruses such as rotavirus, adenovirus, and enteroviruses.297,340,341 The antimicrobial activity of chlorhexidine is not seriously affected by the presence of organic material, including blood. Because chlorhexidine is a cationic molecule, its activity can be reduced by natural soaps, various inorganic anions, non-ionic surfactants, and hand creams containing anionic emulsifying agents.204,339,342 CHGhas been incorporated into a number of hand hygiene preparations. Aqueous or detergent formulations containing 0.5%, 0.75%, or 1% chlorhexidine are more effective than plain soap, but are less effective than antiseptic detergent preparations containing 4%CHG.301,343 Preparations with 2% CHGare slightly less effective than those containing 4% chlorhexidine.344 A scrub agent based on CHG(4%) was shown to be significantly more effective to reduce bacterial count than a povidone iodine (7.5%) scrub agent.247
Chlorhexidine has significant residual activity.273,281–283,285,301,315,343 Addition of low concentrations (0.5–1%) of chlorhexidine to alcohol-based preparations results in significantly greater residual activity than alcohol alone.283,301 When used as recommended, chlorhexidine has a good safety record.339 Little, if any, absorption of the compound occurs through the skin. Care must be taken to avoid contact with the eyes when using preparations with 1% chlorhexidine or greater as the agent can cause conjunctivitis or serious corneal damage. Ototoxicity precludes its use in surgery involving the inner or middle ear. Direct contact with brain tissue and the meninges should be avoided. The frequency of skin irritation is concentration-dependent, with products containing 4% most likely to cause dermatitis when used frequently for antiseptic handwashing.345 True allergic reactions to CHGare very uncommon (see also Part I, Section 14).285,339 Occasional outbreaks of nosocomial infections have been traced to contaminated solutions of chlorhexidine.346–349 Resistance to chlorhexidine has also been reported.350
11.5. Chloroxylenol
Chloroxylenol, also known as para-chloro-meta-xylenol (PCMX), is a halogen-substituted phenolic compound that has been used widely as a preservative in cosmetics and other products and as an active agent in antimicrobial soaps. It was developed in Europe in the late 1920s and has been used in the USA since the 1950s.351
The antimicrobial activity of chloroxylenol is apparently attributable to the inactivation of bacterial enzymes and alteration of cell walls.48 It has good in vitro activity against Gram-positive organisms and fair activity against Gram-negative bacteria, mycobacteria and some viruses.48,351,352 Chloroxylenol is less active against P. aeruginosa, but the addition of ethylene-diaminetetraacetic acid (EDTA) increases its activity against Pseudomonas spp. and other pathogens.
Relatively few articles dealing with the efficacy of chloroxylenol-containing preparations intended for use by HCWs have been published in the last 25 years, and the results of studies have sometimes been contradictory. For example, in experiments where antiseptics were applied to abdominal skin, Davies and colleagues found that chloroxylenol had the weakest immediate and residual activity of any of the agents studied.353. When 30-second handwashes were performed, however, using 0.6% chloroxylenol, 2% CHG or 0.3% triclosan, the immediate effect of chloroxylenol was similar to that of the other agents. When used 18 times/day for five days, chloroxylenol had less cumulative activity than didCHG.354 When chloroxylenol was used as a surgical scrub, Soulsby and colleagues355 reported that 3% chloroxylenol had immediate and residual activity comparable to 4%CHG, while two other studies found that the immediate and residual activity of chloroxylenol was inferior to both CHG and povidone-iodine.344,356 The disparity between published studies may result in part from the various concentrations of chloroxylenol included in the preparations evaluated and to other aspects of the formulations tested, including the presence or absence of EDTA.351,352 Larson concluded that chloroxylenol is not as rapidly active as CHG or iodophors, and that its residual activity is less pronounced than that observed withCHG.351,352 In 1994, the FDA TFM tentatively classified chloroxylenol as a Category IIISE active agent (insufficient data to classify as safe and effective).198 Further evaluation of this agent by the FDA is ongoing.
The antimicrobial activity of chloroxylenol is minimally affected by the presence of organic matter, but is neutralized by nonionic surfactants. Chloroxylenol is absorbed through the skin.351,352 Chloroxylenol is generally well tolerated; some cases of allergic reactions have been reported,357 but they are relatively uncommon.
Chloroxylenol is available in concentrations ranging from 0.3% to 3.75%. In-use contamination of a chloroxylenol-containing preparation has been reported.358
11.6. Hexachlorophene
Hexachlorophene is a bisphenol composed of two phenolic groups and three chlorine moieties. In the 1950s and early 1960s, emulsions containing 3% hexachlorophene were widely used for hygienic handwashing as surgical scrubs and for routine bathing of infants in hospital nurseries. The antimicrobial activity of hexachlorophene is related to its ability to inactivate essential enzyme systems in microorganisms. Hexachlorophene is bacteriostatic, with good activity against S. aureus and relatively weak activity against Gram-negative bacteria, fungi, and mycobacteria.352
Studies of hexachlorophene as a hygienic handwash or surgical scrub demonstrated only modest efficacy after a single handwash.125,313,359 Hexachlorophene has residual activity for several hours after use and gradually reduces bacterial counts on hands after multiple uses (cumulative effect).48,268,359,360 In fact, with repeated use of 3% hexachlorophene preparations, the drug is absorbed through the skin. Infants bathed with hexachlorophene and caregivers regularly using a 3% hexachlorophene preparation for handwashing have blood levels of 0.1–0.6 parts per million (ppm) hexachlorophene.361 In the early 1970s, infants bathed with hexachlorophene sometimes developed neurotoxicity (vacuolar degeneration).362 As a result, in 1972, the FDA warned that hexachlorophene should no longer be used routinely for bathing infants. After routine use of hexachlorophene for bathing infants in nurseries was discontinued, a number of investigators noted that the incidence of S. aureus infections associated with health care in hospital nurseries increased substantially.363,364 In several instances, the frequency of infections decreased when hexachlorophene bathing of infants was reinstituted. However, current guidelines recommend against routine bathing of neonates with hexachlorophene because of its potential neurotoxic effects.365 The agent is classified by the FDA TFM as not generally recognized as safe and effective for use as an antiseptic handwash.198 Hexachlorophene should not be used to bathe patients with burns or extensive areas of abnormal, sensitive skin. Soaps containing 3% hexachlorophene are available by prescription only.352 Due to its high rate of dermal absorption and subsequent toxic effects,70,366 hexachlorophene-containing products should be avoided and hexachlorophene has been banned worldwide.
11.7. Iodine and iodophors
Iodine has been recognized as an effective antiseptic since the 1800s, though iodophors have largely replaced iodine as the active ingredient in antiseptics because iodine often causes irritation and discolouring of skin.
Iodine molecules rapidly penetrate the cell wall of microorganisms and inactivate cells by forming complexes with amino acids and unsaturated fatty acids, resulting in impaired protein synthesis and alteration of cell membranes.367 Iodophors are composed of elemental iodine, iodide or triiodide, and a polymer carrier (complexing agent) of high molecular weight. The amount of molecular iodine present (so-called “free” iodine) determines the level of antimicrobial activity of iodophors. “Available” iodine refers to the total amount of iodine that can be titrated with sodium thiosulfate.368 Typical 10% povidone-iodine formulations contain 1% available iodine and yield free iodine concentrations of 1 ppm.368 Combining iodine with various polymers increases the solubility of iodine, promotes sustained-release of iodine, and reduces skin irritation. The most common polymers incorporated into iodophors are polyvinyl pyrrolidone (povidone) and ethoxylated nonionic detergents (poloxamers).367,368 The antimicrobial activity of iodophors can also be affected by pH, temperature, exposure time, concentration of total available iodine, and the amount and type of organic and inorganic compounds present (e.g. alcohols and detergents).
Iodine and iodophors have bactericidal activity against Gram-positive, Gram-negative and some spore-forming bacteria (clostridia, Bacillus spp.) and are active against mycobacteria, viruses, and fungi.204,367,369–372 However, in concentrations used in antiseptics, iodophors are not usually sporicidal.373 In vivo studies have demonstrated that iodophors reduce the number of viable organisms that may be recovered from HCWs’ hands.280,314,317,320,374 Povidone-iodine 5–10% has been tentatively classified by the FDA TFM as a safe and effective (Category I) active agent for use as an antiseptic handwash and HCW handwash.198 The extent to which iodophors exhibit persistent antimicrobial activity once they have been washed off the skin is a matter of some controversy. In a study by Paulson,344 persistent activity was noted for six hours, but several other studies demonstrated persistent activity for 30–60 minutes after washing hands with an iodophor.137,284,375 In studies where bacterial counts were obtained after individuals wore gloves for 1–4 hours after washing, however, iodophors demonstrated poor persistent activity.48,271,282,360,376–381 The in vivo antimicrobial activity of iodophors is significantly reduced in the presence of organic substances such as blood or sputum.204 Povidone iodine has been found to be less effective than alcohol 60% (v/v) and hydrogen peroxide 3% and 5% on S. epidermidis biofilms.382
Most iodophor preparations used for hand hygiene contain 7.5– 10% povidone-iodine. Formulations with lower concentrations also have good antimicrobial activity, because dilution tends to increase free iodine concentrations.383 As the amount of free iodine increases, however, the degree of skin irritation also may increase.383 Iodophors cause less skin irritation and fewer allergic reactions than iodine, but more irritant contact dermatitis than other antiseptics commonly used for hand hygiene.220 Occasionally, iodophor antiseptics have become contaminated with Gram-negative bacilli as a result of poor manufacturing processes and have caused outbreaks or pseudo-outbreaks of infection.368,384 An outbreak of P. cepacia pseudobacteremia involving 52 patients in four hospitals in New York over six months was attributed to the contamination of a 10% povidone-iodine solution used as an antiseptic and disinfectant solution.384
11.8. Quaternary ammonium compounds
Quaternary ammonium compounds (QACs) are composed of a nitrogen atom linked directly to four alkyl groups, which may vary considerably in their structure and complexity.385 Among this large group of compounds, alkyl benzalkonium chlorides are the most widely used as antiseptics. Other compounds that have been used as antiseptics include benzethonium chloride, cetrimide, and cetylpyridium chloride.48 The antimicrobial activity of these compounds was first studied in the early 1900s, and a QAC for preoperative cleaning of surgeons’ hands was used as early as 1935.385 The antimicrobial activity of this group of compounds appears to be attributable to adsorption to the cytoplasmic membrane, with subsequent leakage of low molecular weight cytoplasmic constituents.385
QACs are primarily bacteriostatic and fungistatic, although they are microbicidal against some organisms at high concentrations.48 They are more active against Gram-positive bacteria than against Gram-negative bacilli. QACs have relatively weak activity against mycobacteria and fungi and have greater activity against lipophilic viruses (). Their antimicrobial activity is adversely affected by the presence of organic material, and they are not compatible with anionic detergents.48,385
Antimicrobial activity and summary of properties of antiseptics used in hand hygiene.
A QAC is present as a supplement in some commercially available alcohol-based handrubs. A study on the population kinetics of skin flora on gloved hands indicated that the effect of an alcohol-based handrub containing mecetronium etilsulfate (isopropanol 45% wt/wt plus n-propanol 30% wt/wt plus mecetronium etilsulfate 0.2% wt/wt ) was not significantly different from n-propanol 60% v/v.227
Depending on the QAC type and formulation, the antimicrobial efficacy can be severely affected in the presence of hard water (if it is a diluted product) and fatty materials. Later generations of QACs, e.g. didecyldimethyl ammonium chloride (DDAC), have stronger antimicrobial activity and good performance in the presence of hard water and organic soiling, but their activity has been studied on inanimate surfaces only.
In 1994, the FDA TFM tentatively classified benzalkonium chloride and benzethonium chloride as Category IIISE active agents (insufficient data to classify as safe and effective for use as an antiseptic handwash).198 Further evaluation of these agents by the FDA is in progress.
In general, QACs are relatively well tolerated. Unfortunately, because of weak activity against Gram-negative bacteria, benzalkonium chloride is prone to contamination by these organisms and a number of outbreaks of infection or pseudo-infection have been traced to QACs contaminated with Gram-negative bacilli.386–388 For this reason, these compounds have seldom been used for hand antisepsis during the last 15–20 years in the USA. More recently, newer hand hygiene products containing benzalkonium chloride or benzethonium chloride have been introduced for use by HCWs. A recent clinical study performed among surgical ICU HCWs found that cleaning hands with antimicrobial wipes containing a QAC was almost as effective as handwashing with plain soap and water, and that both were significantly less effective than decontaminating hands with an alcohol-based handrub.389 One laboratory-based study reported that an alcohol-free handrub product containing a QAC was efficacious in reducing microbial counts on the hands of volunteers.390 Further studies of such products are needed to determine if newer formulations are effective in health-care settings.
QACs have been used as antiseptics to reduce the bioburden on skin (e.g. for wound cleansing and on mucous membrane as mouthwashes for the control of dental plaque). They are also extensively used as disinfectants (“spray & wipe”) for household, industrial, and health-care surfaces, as well as for food surface disinfection, as most formulations do not require to be rinsed off with water after application.391 The presence of low-level residues may allow the selective development of bacterial strains with greater tolerance of QACs over time; intrinsic and acquired resistance mechanisms have been described.392,393
In general, QACs are relatively well tolerated and have low allergenic potential. In higher concentrations, though, they can cause severe irritation to skin and mucous membranes.
11.9. Triclosan
Triclosan (chemical name 2,4,4′–trichloro-2′-hydroxydiphenyl ether) is known commercially as Irgasan DP-300. It is a nonionic, colourless substance developed in the 1960s; it is poorly soluble in water, but dissolves well in alcohols. Concentrations ranging from 0.2% to 2% have antimicrobial activity. Triclosan has been incorporated in detergents (0.4% to 1%) and in alcohols (0.2% to 0.5%) used for hygienic and surgical hand antisepsis or preoperative skin disinfection; it is also used for antiseptic body baths to control MRSA. This agent is incorporated into some soaps (at a 1% w/v concentration) and a variety of other consumer products (deodorants, shampoos, lotions, etc.), as well as being integrated also into various dressings and bandages for release over time onto the skin.
Triclosan enters bacterial cells and affects the cytoplasmic membrane and synthesis of RNA, fatty acids, and proteins.394 Recent studies suggest that this agent’s antibacterial activity is attributable in large part to binding to the active site of enoyl-acyl carrier protein reductase.395,396
Triclosan has a fairly broad range of antimicrobial activity (), but tends to be bacteriostatic.48 Minimum inhibitory concentrations (MICs) range from 0.1 to 10 μg/ml, while minimum bactericidal concentrations are 25–500 μg/ml. Triclosan’s activity against Gram-positive organisms (including MRSA) is greater than against Gram-negative bacilli, particularly P. aeruginosa.48,394 The agent possesses reasonable activity against mycobacteria and Candida spp., but has little activity against filamentous fungi and most viruses of nosocomial significance. Triclosan (0.1%) reduces bacterial counts on hands by 2.8 log10 after a 1-minute hygienic handwash.48 In a number of studies, log reductions achieved have been lower than with chlorhexidine, iodophors or alcohol-based products.48,137,223,354,397/In 1994, the FDA TFM tentatively classified triclosan up to 1% as a Category IIISE active agent (insufficient data to classify as safe and effective for use as an antiseptic handwash).198 Further evaluation of this agent by the FDA is under way. Similar to chlorhexidine, triclosan has persistent activity on the skin. Its activity in hand-care products is affected by pH, the presence of surfactants or humectants, and the ionic nature of the particular formulation.48,394 Triclosan’s activity is not substantially affected by organic matter, but may be inhibited by sequestration of the agent in micelle structures formed by surfactants present in some formulations. Most formulations containing less than 2% triclosan are well tolerated and seldom cause allergic reactions. A few reports suggest that providing HCWs with a triclosan-containing preparation for hand antisepsis has led to decreased infections caused by MRSA.181,182 Triclosan’s lack of potent activity against Gram-negative bacilli has resulted in occasional reports of contaminated triclosan.398
A recent study compared an antibacterial soap containing triclosan with a non-antibacterial soap and concluded that the former did not provide any additional benefit.399 Concerns have been raised about the use of triclosan, because of the development of bacterial resistance to low concentrations of biocide and cross-resistance to some antibiotics. For example, Mycobacterium smegmatis mutations in inhA gene leading to triclosan resistance are known to carry resistance also to isoniazid.400 Increased tolerance (i.e increased MICs) to triclosan due to mutations in efflux pumps has been reported in E. coli and P. aerugninosa.401 Laboratory studies involving exposure of some microorganisms to subinhibitory concentrations of triclosan have resulted in increased triclosan MICs. However, the clinical relevance of increased triclosan MICs generated in the laboratory is unclear, since affected strains remain susceptible to in-use concentrations of triclosan.401,402 Further research dealing with the relationship between triclosan use and antimicrobial resistance mechanisms is warranted, and surveillance for triclosan-resistant pathogens in clinical and environmental settings is needed.
11.10. Other agents
More than 100 years after Semmelweis demonstrated the impact of rinsing hands with a solution of chlorinated lime on maternal mortality related to puerperal fever, Lowbury and colleagues403 studied the efficacy of rubbing hands for 30 seconds with an aqueous hypochlorite solution. They found that the solution was no more effective than rinsing with distilled water. Rotter404 subsequently studied the regimen used by Semmelweis, which called for rubbing hands with a 4% hypochlorite solution405 until the hands were slippery (approximately 5 minutes). He found that the regimen was 30 times more effective than a 1-minute rub using 60% isopropanol. However, because hypochlorite solutions tend to be very irritating to the skin when used repeatedly and have a strong odour, they are seldom used for hand hygiene today. A number of other agents are being evaluated by the FDA for use in antiseptics related to health care.198 However, the efficacy of these agents has not been evaluated adequately for use in hand hygiene preparations intended for use by HCWs. Further evaluation of some of these agents may be warranted. Products that utilize different concentrations of traditional antiseptics (e.g. low concentrations of iodophor) or contain novel compounds with antiseptic properties are likely to be introduced for use by HCWs. For example, preliminary studies have demonstrated that adding silver-containing polymers to an ethanol carrier (Surfacine) results in a preparation that has persistent antimicrobial activity on animal and human skin.406 A unique chlorhexidine-loaded, nanocapsule-based gel showed immediate bactericidal effect, comparable to isopropanolol 60% v/v against aerobic bacteria; surviving anaerobic bacteria were significantly lower compared with ethanol-based gel 62% v/v. Persistant bactericidal effect was observed throughout the 3-hour test period. The immediate and sustained antibacterial effect was explained by an efficient chlorhexidine carrier system which improved the drug targeting to bacteria.407 The clinical significance of these findings deserves further research. New compounds with good in vitro activity must be tested in vivo to determine their abilities to reduce transient and resident skin flora on the hands of caregivers.
11.11. Activity of antiseptic agents against spore-forming bacteria
The increasing incidence of C. difficile-associated diarrhoea in health-care facilities in several countries, and the occurrence in the USA of human Bacillus anthracis infections related to contaminated items sent through the postal system, have raised concerns about the activity of antiseptic agents against spores. The increasing morbidity and mortality of C. difficile-associated disease in the USA, Canada, and some European countries since 2001 has been especially attributed to more frequent outbreaks and the emergence of a new, more virulent strain (ribotype 027).408 Epidemic strains differ among countries: for instance, while in Canada and the Netherlands ribotype 027 is predominant, the United Kingdom detected three different strains (ribotype 001, 027 and 106) responsible for 70% of C. difficile-associated diarrhoea.409–417
Apart from iodophors, but at a concentration remarkably higher than the one used in antiseptics,373 none of the agents (including alcohols, chlorhexidine, hexachlorophene, chloroxylenol, and triclosan) used in antiseptic handwash or antiseptic handrub preparations is reliably sporicidal against Clostridium spp. or Bacillus spp.287,339,418,419 Mechanical friction while washing hands with soap and water may help physically remove spores from the surface of contaminated hands.110,420,421 This effect is not enhanced when using medicated soap.420 Contact precautions are highly recommended during C. difficile-associated outbreaks, in particular, glove use (as part of contact precautions) and handwashing with a non-antimicrobial or antimicrobial soap and water following glove removal after caring for patients with diarrhoea.422,423 Alcohol-based handrubs can then be exceptionally used after handwashing in these instances, after making sure that hands are perfectly dry. Moreover, alcohol-based handrubs, now considered the gold standard to protect patients from the multitude of harmful resistant and non-resistant organisms transmitted by HCWs’ hands, should be continued to be used in all other instances at the same facility. Discouraging their widespread use, just because of the response to diarrhoeal infections attributable to C. difficile, will only jeopardize overall patient safety in the long term.
The widespread use of alcohol-based handrubs was repeatedly given the major blame for the increase of C. difficile-associated disease rates because alcohol preserves spores and is used in the laboratory to select C. difficile spores from stools.424,425 Although alcohol-based handrubs may not be effective against C. difficile, it has not been shown that they trigger the rise of C. difficile-associated disease.426–429C. difficile-associated disease rates began to rise in the USA long before the wide use of alcohol-based handrubs.430,431 One outbreak with the epidemic strain REA-group B1 (≃ribotype 027) was successfully managed while introducing alcohol-based handrub for all patients other than those with C. difficile-associated disease.427 Furthermore, abandoning alcohol-based handrub for patients other than those with C. difficile-associated disease would do more harm than good, considering the dramatic impact on overall infection rates observed through the recourse to handrubs at the point of care.320
A guide on how to deal with C. difficile outbreaks, including frequently asked questions on hand hygiene practices, is provided in Appendix 2.
A recent study demonstrated that washing hands with either non-antimicrobial soap or antimicrobial soap and water reduced the amount of B. atrophaeus (a surrogate for B. anthracis) on hands, whereas an alcohol-based handrub was not effective.432 Accordingly, HCWs with suspected or documented exposure to B. anthracis-contaminated items should wash their hands with a non-antimicrobial or antimicrobial soap and water.
11.12. Reduced susceptibility of microorganisms to antiseptics
Reduced susceptibility of bacteria to antiseptic agents can be an intrinsic characteristic of a species, or can be an acquired trait.433 A number of reports have described strains of bacteria that appear to have acquired reduced susceptibility to antiseptics such as chlorhexidine, QAC, or triclosan when defined by MICs established in vitro.433–436 However, since “in-use” concentrations of antiseptics are often substantially higher than the MICs of strains with reduced antiseptic susceptibility, the clinical relevance of the in vitro findings may be inaccurate. For example, some strains of MRSA have chlorhexidine and QAC MICs that are several-fold higher than methicillin-susceptible strains, and some strains of S. aureus have elevated MICs to triclosan.433,434,437 However, such strains were readily inhibited by in-use concentrations of these antiseptics.433,434 Very high MICS for triclosan were reported by Sasatsu and colleagues,438 and the description of a triclosan-resistant bacterial enzyme has raised the question of whether resistance may develop more readily to this agent than to other antiseptic agents.396 Under laboratory conditions, bacteria with reduced susceptibility to triclosan carry cross-resistance to antibiotics.439,440 Reduced triclosan susceptibility or resistance was detected in clinical isolates of methicillin-resistant S. epidermidis and in MRSA, respectively.441,442 Of additional concern, exposing Pseudomonas strains containing the MexAB-OprM efflux system to triclosan may select for mutants that are resistant to multiple antibiotics, including fluoroquinolones.436,439,440 Nevertheless, a recent study failed to demonstrate a statistically significant association between elevated triclosan MICs and reduced antibiotic susceptibility among staphylococci and several species of Gram-negative bacteria.443 Clearly, further studies are necessary to determine if reduced susceptibility to antiseptic agents is of epidemiological importance, and whether or not resistance to antiseptics may influence the prevalence of antibiotic-resistant strains.433 Periodic surveillance may be needed to ensure that this situation has not changed.444
11.13. Relative efficacy of plain soap, antiseptic soaps and detergents, and alcohols
Comparing the results of laboratory studies dealing with the in vivo efficacy of plain soap, antimicrobial soaps, and alcohol-based handrubs may be problematic for various reasons. First, different test methods produce different results,445 especially if the bacteriostatic effect of a formulation is not (or not sufficiently) abolished – either by dilution or chemical neutralizers – prior to quantitative cultivation of post-treatment samples. This leads to results that might overstate the efficacy of the formulation,446 Second, the antimicrobial efficacy of a hand antiseptic agent is significantly different among a given population of individuals.315 Therefore, the average reductions of bacterial release by the same formulation will be different in different laboratories or in one laboratory with different test populations.447 Inter-laboratory results will be comparable only if they are linked up with those of a reference procedure performed in parallel by the same individuals in a cross-over designed test and compared intra-individually. Summarizing the relative efficacy of agents in each study can provide a useful overview of the in vivo activity of various formulations ( and ). From there, it can be seen that antiseptic detergents are usually more efficacious than plain soap and that alcohol-based rubs are more efficacious than antiseptic detergents. A few studies show that chlorhexidine may be as effective as plain soap against MRSA, but not as effective as alcohol and povidone iodine.448 Studies conducted in the community setting bring additional findings on the topic of the relative efficacy of different hand hygiene products. Some indicate that medicated and plain soaps are roughly equal in preventing the spread of childhood gastrointestinal and upper respiratory tract infections or impetigo249,449,450. This suggests that the health benefits from clean hands probably result from the simple removal of potential pathogens by handwashing rather than their in situ inactivation by medicated soaps. Other studies clearly demonstrated the effectiveness of alcohol-based handrubs used for hand hygiene in schools in reducing the incidence of gastrointestinal and/or respiratory diseases and absenteeism attributable to these causes.451–454
Hygienic handrub efficacy of various agents in reducing the release of test bacteria from artificially-contaminated hands.
In most studies on hygienic hand antisepsis that included plain soap, alcohols were more effective than soap ( and ). In several trials comparing alcohol-based solutions with antimicrobial detergents, alcohol reduced bacterial counts on hands to a greater extent than washing hands with soaps or detergents containing hexachlorophene, povidone-iodine, CHG(CHG) or triclosan. In a cross-over study comparing plain soap with one containing 4% CHG, unexpectedly, the latter showed higher final CFU counts after use of CHG-soap compared with plain soap, but the comparative CFU log reduction was not provided to permit conclusions concerning relative efficacy.455 In another clinical study in two neonatal intensive care units comparing an alcohol rub with 2% CHG-soap, no difference was found either in infection rates or in microbial counts from nurses’ hands.456 Of note, the ethanol concentration (61%) of the sanitizer was low and the chemicals to neutralize CHG washed from the hands into the sampling fluids might not have been appropriate. However, a randomized clinical trial comparing the efficacy of handrubbing versus conventional handwashing with antiseptic soap showed that the median percentage reduction in bacterial contamination was significantly higher with handrubbing than with hand antisepsis with 4% CHG-soap.457 In another trial to compare the microbiological efficacy of handrubbing with an alcohol-based solution and handwashing with water and unmedicated soap in HCWs from different wards, with particular emphasis on transient flora, handrubbing was more efficacious than handwashing for the decontamination of HCWs’ hands.152 In studies dealing with antimicrobial-resistant organisms, alcohol-based products reduced the number of multidrug-resistant pathogens recovered from the hands of HCWs more effectively than handwashing with soap and water.225,374,458 An observational study was conducted to assess the effect of an alcohol-based gel handrub on infection rates attributable to the three most common multidrug-resistant bacteria (S. aureus, K. pneumoniae, and P. aeruginosa) in Argentina.459 Two periods were compared, 12 months before (handwashing with soap and water) and 12 months after starting alcohol gel use. The second period (alcohol gel use) showed a significant reduction in the overall incidence rates of K. pneumoniae with extended-spectrum beta-lactamase (ESBL) infections, in particular bacteraemias. Nevertheless, on the basis of this study, the authors could not conclude whether this was a result of alcohol gel itself or an increase in hand hygiene compliance.
The efficacy of alcohols for surgical hand antisepsis has been reviewed in numerous studies.48,268,271,280–286,301,313,316,460–463 In many of these studies, bacterial counts on the hands were determined immediately after using the product and again 1–3 hours later. The delayed testing is performed to determine if regrowth of bacteria on the hands is inhibited during operative procedures; this has been shown to be questionable by in vivo experiments only if a suitable neutralizer is used to stop any prolonged activity in the sampling fluids and on the counting plates.227 The relative efficacy of plain soap, antimicrobial soaps, and alcohol-based solutions to reduce the number of bacteria recovered from hands immediately after use of products for surgical hand preparation is shown in . A comparison of five surgical hand antisepsis products – two alcohol-based handrubs and three handwashes (active ingredient triclosan, CHG or povidone-iodine) – by EN 12791, an in vivo laboratory test, showed that preparations containing povidone-iodine and triclosan failed the test, although all products passed the in vitro suspension test of prEN 12054. Better results were achieved with the alcohol-based handrubs.464 Alcohol-based solutions were more effective than washing hands with plain soap in all studies, and reduced bacterial counts on hands to a greater extent than antimicrobial soaps or detergents in most experiments.268,271,280–286,301,313,316,461–463
shows the log10 reductions in the release of resident skin flora from clean hands immediately and 3 hours after use of surgical handrub products. Alcohol-based preparations proved more efficacious than plain soap and water, and most formulations were superior to povidone-iodine- or CHG-containing detergents. Among the alcohols, a clear positive correlation with their concentration is noticeable and, when tested at the same concentration, the range of order in terms of efficacy is: ethanol is less efficacious than isopropanol, and the latter is less active than n-propanol.
Studies comparing the relative efficacy of plain soap or antimicrobial soap versus alcohol-containing products in reducing counts of bacteria recovered from hands immediately after use of products for preoperative surgical hand preparation.
Efficacy of surgical handrub solutions in reducing the release of resident skin flora from clean hands.
