Effectiveness of hand washing and disinfection methods in removing transient bacteria after patient nursing

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Staph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone. In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci were more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments. The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection.     

Comparison of two methods for assessing the removal of total organisms and pathogens from the skin.

A standard hand-wash sampling technique was compared with a simple finger-streak sampling method in assessing the relative effectiveness of a number of alternative preparations used for disinfecting the surgeon''s hands (alcoholic 0.5% chlorhexidine, alcoholic 0.1% tetrabrom-o-methyl phenol, a 4% chlorhexidine detergent solution, aqueous 0.5% chlorhexidine, 2% ''Irgasan'' detergent solution and, as control, bar soap). There was a fairly good correlation between the results of assessment by the two methods after a single disinfection and after six disinfections, three on one day and three on the next. Significant differences were shown in 21 comparisons between treatments when the hand-wash sampling test was used, and 16 of these comparisons also showed a significant difference by the finger-streak test. Staphylococcus aureus was found in hand samplings from 5 out of 8 nurses in the Burns Unit of Birmingham Accident Hospital by the hand-wash sampling method and from 2 of the same 8 nurses by the finger-streak method; the numbers were small, and no Staph. aureus were isolated from the same hands after 1 min. wash in 70% ethyl alcohol. Similar sampling on 29 nurses in other wards showed Staph. aureus on 3 nurses (one in large numbers) by the hand-wash technique and on 1 nurse by the finger-streak test; in only 1 nurse whose hands showed Staph. aureus before disinfection was the organism found, by hand-wash sampling, after disinfection. Parallel sampling of nurses'' hands after washing with soap and water and after disinfection with 95% ethanol showed larger numbers of Staph. aureus in a hospital for skin diseases than in a general hospital, and a lower incidence and somewhat lower density of Staph. aureus after ethanol treatment than after washing with soap and water; Gram-negative bacilli, on the other hand, were commoner on hands in the general than in the skin hospital, and present in much smaller numbers after disinfection with ethanol than after washing with soap and water. Antibiotic sensitivity tests showed the frequent recurrence on the hands of some nurses of multi-resistant Staph. aureus with resistance patterns similar to those found in infective lesions in some of the patients; different sensitivity patterns were usually found in staphylococci isolated from the nose. Even in wards where many patients were infected, carriage by nurses'' hands of a particular strain of Staph. aureus did not seem to last for more than a few days.     

3种不同手卫生方法效果观察

目的 观察3种不同手卫生处置方法的效果,为医务人员提供便利、可靠的手卫生方法.方法 选择临床医护人员90名,随机分为3组,设肥皂洗手组30人,卫生手消毒组30人,先洗手后卫生手消毒组30人;洗手组使用肥皂,卫生手消毒组使用速干手消毒剂,先洗手后卫生手消毒组是先用肥皂再用速干手消毒剂洗手,干后立即用含相应中和剂的无菌洗脱液的无菌棉拭子采样双手标本送检,37℃培养48 h,观察3组人员手部细菌菌落数.结果 肥皂洗手、卫生手消毒、先洗手后卫生手消毒合格率分别为76.7％、93.3％、100.0％,均未检出致病菌;肥皂洗手与卫生手消毒比较、卫生手消毒与先洗手后卫生手消毒比较差异无统计学意义,肥皂洗手与先洗手后卫生手消毒比较差异有统计学意义(P＜0.05).结论 3种手卫生方法均可用于临床医务人员的手部清洗除菌,先洗手后卫生手消毒效果最佳,卫生手消毒效果优于肥皂洗手.     

The importance of soap selection for routine hand hygiene in hospital.

Five different types of liquid soap were studied in hospital wards, each during two months'' use. Altogether 1306 finger print samples were taken from the hands of the staff by sampling twice a week and the acceptability of the soaps was measured by a questionnaire. During the use of different soaps only slight differences were found in the numbers of total bacteria or in the occurrence of Staph. aureus and gram-negative bacilli on the hands. During the use of the emulsion-type product studied, several persons who had dermatological problems had lower mean bacterial counts of the fingers than during the use of the other soaps. This soap was also favourably accepted by the staff. After over one year''s use of pine oil soap and alcohol, the staff of the hospital was satisfied with the method. However, several persons with skin problems admitted to not using soap or alcohol. The considerable differences found in the acceptability of soaps imply that for use in hospital the choice of a soap acceptable to the nursing staff is important in promoting proper hand hygiene.     

Application of the hygienic hand-disinfection test to the gloved hand

The Austrian Standard Hygienic Hand-Disinfection Test was adapted for comparing the effect of washing artificially contaminated hands (using Escherichia coli) with contaminated gloved hands, using liquid soap and rinsing with water. Tests showed that a single soap wash completely removed all the bacteria from the glove, and was more than 1000 times more effective on the glove than on the hand.     

Hand disinfection: a comparison of various agents in laboratory and ward studies

The efficacy of 14 handwashing or disinfectant preparations was compared in laboratory tests on staff volunteers. The test organism, Escherichia coli, was applied to the fingertips and log reductions (LR) were measured following treatment with the test agent and control preparations (70% isopropanol and non-medicated bar soap). Alcoholic preparations, particularly n-propanol and isopropanol were the most effective showing LRs of 3.1-3.8. Chlorhexidine (LR 2.9) and povidone-iodine detergent preparations were significantly more effective than non-medicated soap (LR 2.1), but triclosan products were not. In addition the residual effect of several of these formulations was assessed after 10 applications by comparing the survival of E. coli on the fingertips over a 32-min period. This number of handwashes compares favourably with those recorded during an 8 h nursing shift. Chlorhexidine-detergent consistently showed the best residual activity. Alcoholic formulations showed little or no residual effect. The survival studies show that on the whole gram-positive organisms (Staphylococcus aureus and Candida albicans) survive better on the skin than Gram-negative bacilli (GNB). However, it would seem that GNB which are considered to be residents (Acinetobacter calcoaceticus and Enterobacter spp.) survive much better than many other GNB (Pseudomonas aeruginosa, E. coli and Proteus vulgaris). The Klebsiella species varied in survival times. Random sampling of ward staff hands showed that contamination with S. aureus and GNB was greater in dermatological and general wards than in an isolation unit, where handwashing or disinfection was carried out after every patient contact. No cross-infection occurred in the isolation ward during periods of study in which 70% alcohol, chlorhexidine-detergent and non-medicated soap were used.     

Nosocomial Serratia marcescens infections associated with extrinsic contamination of a liquid nonmedicated soap.

OBJECTIVE: To determine the role of nonmedicated soap as a source of Serratia marcescens nosocomial infections (NIs) in hospital units with endemic S marcescens NI and to examine the mechanisms of soap colonization. SETTING: University-affiliated tertiary-care hospitals. METHODS: A prospective case-control study and an environmental investigation were performed to assess the relationship between S marcescens NIs in hospital units and S marcescens-contaminated soap. Soap-bottle use and handwashing practices were reviewed. Cultures of healthcare workers' (HCWs) hands were obtained before and after hand washing with soap. RESULTS: 5 of 7 hospital units with S marcescens NIs had soap bottles contaminated with S marcescens, compared to 1 of 14 other units (P=.006). After hand washing with an S marcescens-contaminated soap pump, HCWs' hands were 54 times more likely to be contaminated with S marcescens (P<.001). CONCLUSIONS: Extrinsic contamination of a non-medicated liquid soap by S marcescens resulted in handborne transmission of S marcescens NIs by HCWs in our setting. This finding led to the application of strict guidelines for nonmedicated soap use and to the reinforcement of alcoholic hand disinfection.     

两种皮肤消毒法及干预措施对消毒效果影响的研究

目的探讨连续与间断待干两种常规皮肤消毒法的消毒效果,在确定何种消毒方法的基础上,研究消毒及采用肥皂洗手方式干预后的消毒效果。方法受试者分别用连续和间断待干两种方式消毒手背,用肥皂洗手方式干预后,进行1次和2次手背消毒;分别对各组受试者的408个手背消毒区采样进行细菌培养,分析各组间的消毒效果。结果连续消毒法比间断待干消毒法显著节省时间(P0.05),消毒效果差异无统计学意义;在此基础上行洗手干预,消毒1次组的污染数显著高于消毒2次组和洗手干预后消毒1次组(P0.05),并显著的高于洗手干预后消毒2次组(P0.01)。结论连续消毒比间断待干消毒法节省时间,效果相同,洗手干预后可显著增强消毒效果。     

Washing with contaminated bar soap is unlikely to transfer bacteria

Recent reports of the isolation of microorganisms from used soap bars have raised the concern that bacteria may be transferred from contaminated soap bars during handwashing. Since only one study addressing this question has been published, we developed an additional procedure to test this concern. In our new method prewashed and softened commercial deodorant soap bars (0.8% triclocarban) not active against Gram-negative bacteria were inoculated with Escherichia coli and Pseudomonas aeruginosa to give mean total survival levels of 4.4 X 10(5) c.f.u. per bar which was 70-fold higher than those reported on used soap bars. Sixteen panelists were instructed to wash with the inoculated bars using their normal handwashing procedure. After washing, none of the 16 panelists had detectable levels of either test bacterium on their hands. Thus, the results obtained using our new method were in complete agreement with those obtained with the previously published method even though the two methods differ in a number of procedural aspects. These findings, along with other published reports, show that little hazard exists in routine handwashing with previously used soap bars and support the frequent use of soap and water for handwashing to prevent the spread of disease.     

Prevention of irritant contact dermatitis among health care workers by using evidence-based hand hygiene practices: a review

Irritant contact dermatitis is often found on the hands of healthcare workers and is generally caused by frequent hand washing, gloves, aggressive disinfectants or detergents. Alcohols have only a marginal irritation potential, although they may cause a burning sensation on pre-irritated skin. A burning sensation when using alcohols therefore, suggests that the skin barrier is already damaged. Two options for hand hygiene are generally available in clinical practice: (1) hand washing with some type of soap and water or (2) hand disinfection with alcohol-based hand rubs. Most clinical situations require the use of an alcohol-based hand rub for decontamination, which is especially useful for reducing the nosocomial transmission of various infectious agents. Washing one's hands should be the exception, to be performed only when they are visibly soiled or contaminated with proteinaceous material, or visibly soiled with blood or other body fluids. The overall compliance rate in hand hygiene is around 50%, which is far too low. In addition, healthcare workers quite often wash their hands with soap and water, when they should use an alcohol-based hand rub. This not only adds to the degree of skin irritation, but is also potentially dangerous for patients, due to the low efficacy of hand washing when compared to hand disinfection with alcohol rubs. Adhering to evidence-based hand hygiene protocols and following international guidelines on hand hygiene practices therefore, can help prevent irritant contact dermatitis among healthcare workers.     

Successful hand hygiene in hospital

Healthy skin and especially hand skin is a good individual barrier. On terms of healthy skin the hand washing and disinfection methods will effectively remove transient and lower resident flora if needed. Disturbed skin on the other hand may harbor pathogens like gram negative rods or Staphylococcus aureus strains as part of resident flora. Even the best hand hygiene methods will fail. There for other more gentle hand hygiene methods should be tested in use situations too. The alternatives are especially important for those layable to skin problems during dry and cold periods. Preliminary emulsion cleansing and then rinsing to traditional water and soap washing has shown to be a possibly hand skin caring alternative, which results in good reduction of bacteria when connected with alcohol disinfection.     

Efficacy of low-concentration iodophors for germicidal hand washing

The efficacy of iodophor germicides containing different concentrations of available iodine against transient (inoculated) bacteria and the natural hand microflora was compared with chlorhexidine gluconate (2 and 4%) liquid detergent (Hibitane), non-germicidal soap and a tap water rinse. The tap water rinse was ineffective compared with all other treatments. Only 4% chlorhexidine gluconate liquid detergent and iodophor containing 0.75% available iodine were significantly better than the non-germicidal soap for reduction of transient bacteria, Escherichia coli and Pseudomonas fluorescens, that had been inoculated onto hands. These agents also caused a significant reduction in the number of 'natural' microorganisms released from hands after a standard 15 s hand wash. The low-concentration iodophor products and the product containing 2% chlorhexidine gluconate failed to give results significantly better than the non-germicidal control soap. Baird-Parker medium and standard aerobic plate counts were highly correlated (r = 0.82), so that for studies of Gram-negative bacteria inoculated onto hands as a transient microflora, counts on Baird-Parker medium give a reasonable indication of the natural (residual) hand microflora.     

Contamination of hospital linen by Bacillus cereus.

An investigation into two cases of post-operative Bacillus cereus meningitis revealed that hospital linen laundered by a batch continuous washing machine was heavily contaminated by B. cereus spores. The washing machine, detergents, other chemical additives and the water supply were eliminated as the source of contamination. It was found that the linen introduced into the washing machine had a high B. cereus spore content and that this was still present after the wash process. The spores were not killed by either the heat disinfection stage of the wash or the addition of chemical disinfectants and were not removed by the dilution in the process. The multiplication of B. cereus was thought to have occurred on used, damp linen stored in plastic bags, particularly when ambient temperatures were high. An increase in the water flow through the washing machine was the only measure associated with a decrease in B. cereus on laundered linen.     

Microbiological analysis of blood culture obtained from children hospitalized at the Gastroenterology, Oncology and Daily Chemotherapy Wards of the Children's Memorial Health Institute in the years 1999-2002

The aim of the study was to examine correlations between the use of different kinds of intravascular catheters and the type of microorganisms isolated from blood cultures. Blood samples obtained from gastroenterology, oncology and daily chemotherapy wards were examined. The samples were taken from catheter and peripheral blood in situations where blood infection was suspected. In positive blood samples Gram-positive bacteria, especially methicillin-resistant coagulase negative staphylococci, were dominant. Enterobacteriaceae (Klebsiella sp., E. coli, Enterobacter sp.) were the most often isolated among Gram-negative bacteria. The share of Staphylococcus aureus, Gram-negative bacilli and fungi was greater in the case of samples taken from catheters. The domination of CNS is frequently connected with catheter colonisation or contamination of samples. Intravascular catheters predispose to Staphylococcus aureus, Gram-negative rods and fungal infections.     

Efficacy of low-concentration iodophors for germicidal hand washing.

The efficacy of iodophor germicides containing different concentrations of available iodine against transient (inoculated) bacteria and the natural hand microflora was compared with chlorhexidine gluconate (2 and 4%) liquid detergent (Hibitane), non-germicidal soap and a tap water rinse. The tap water rinse was ineffective compared with all other treatments. Only 4% chlorhexidine gluconate liquid detergent and iodophor containing 0.75% available iodine were significantly better than the non-germicidal soap for reduction of transient bacteria, Escherichia coli and Pseudomonas fluorescens, that had been inoculated onto hands. These agents also caused a significant reduction in the number of ''natural'' microorganisms released from hands after a standard 15 s hand wash. The low-concentration iodophor products and the product containing 2% chlorhexidine gluconate failed to give results significantly better than the non-germicidal control soap. Baird-Parker medium and standard aerobic plate counts were highly correlated (r = 0.82), so that for studies of Gram-negative bacteria inoculated onto hands as a transient microflora, counts on Baird-Parker medium give a reasonable indication of the natural (residual) hand microflora.     

Contamination of protective clothing and nurses' uniforms in an isolation ward

Staphylococcus aureus was frequently isolated, usually in small numbers, from cotton gowns (12.6 per cent), plastic aprons (9.2 per cent) and nurses' uniforms (15 per cent). Gram-negative bacilli were infrequently isolated. Contamination of the protective clothing did not increase when used over periods of up to 11 days. Fewer organisms were recovered from the front of nurses' uniforms when plastic aprons instead of gowns were worn, but gowns provided better shoulder protection. However, no differences were observed in isolations of Staph, aureus or Gram-negative bacilli from these sites.     

The effectiveness of ethanol gauze for hand disinfection in surgical wards

The effectiveness of ethanol gauze in removing transient bacteria on the hands was investigated in a surgical ward during clinical nursing rounds. Two nurses with similar duties were selected as subjects for each round; one disinfected her hands with ethanol gauze when moving between patients while the other immersed her hands in 0.05% aqueous chlorhexidine gluconate when aware of contaminating her hands. Hand samples were taken after preliminary disinfection before the round, and again after the round on 37 occasions. Pseudomonas aeruginosa and Staphylococcus aureus were not detected in nurses using ethanol gauze, except in one nurse where S. aureus was isolated from both the pre- and postround hand culture. Both organisms were detected on four occasions from the postround hand cultures in the chlorhexidine group. Acinetobacter anitratus was not removed by pre-round disinfection, and was found on five and 11 occasions from the postround hand cultures in the ethanol gauze and chlorhexidine groups, respectively.     

Distribution of multi-resistant Gram-negative versus Gram-positive bacteria in the hospital inanimate environment

We prospectively studied the difference in detection rates of multi-resistant Gram-positive and multi-resistant Gram-negative bacteria in the inanimate environment of patients harbouring these organisms. Up to 20 different locations around 190 patients were surveyed. Fifty-four patients were infected or colonized with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE) and 136 with multi-resistant Gram-negative bacteria. The environmental detection rate for MRSA or VRE was 24.7% (174/705 samples) compared with 4.9% (89/1827 samples) for multi-resistant Gram-negative bacteria (P<0.001). Gram-positive bacteria were isolated more frequently than Gram-negatives from the hands of patients (P<0.001) and hospital personnel (P=0.1145). Environmental contamination did not differ between the intensive care units (ICUs) and the general wards (GWs), which is noteworthy because our ICUs are routinely disinfected twice a day, whereas GWs are cleaned just once a day with detergent. Current guidelines for the prevention of spread of multi-resistant bacteria in the hospital setting do not distinguish between Gram-positive and Gram-negative isolates. Our results suggest that the inanimate environment serves as a secondary source for MRSA and VRE, but less so for Gram-negative bacteria. Thus, strict contact isolation in a single room with complete barrier precautions is recommended for MRSA or VRE; however, for multi-resistant Gram-negative bacteria, contact isolation with barrier precautions for close contact but without a single room seems sufficient. This benefits not only the patients, but also the hospital by removing some of the strain placed on already over-stretched resources.     

Surgical hand disinfection: effect of sequential use of two chlorhexidine preparations

The antimicrobial efficacy of three 'two-phase' surgical hand disinfection procedures was compared, in a volunteer study, to 60% n-propanol, applied for 5 min, which is the reference hand-disinfection procedure used in Austria and West Germany (FRG). The procedures involved sequential use of unmedicated soap or a disinfectant-detergent containing 4% chlorhexidine gluconate (CHX; 'Hibiscrub') followed by a handrub preparation containing 70% w/w isopropanol plus 0.5% CHX ('Hibisol'). The immediate and sustained effects (3 h) of washing with unmedicated soap (3 min) followed by rubbing on 'Hibisol' (4 min) were significantly smaller (log10 reductions of 1.72 and 1.12) than with each of the other procedures. Use of 'Hibiscrub' (3 min) and 'Hibisol' (4 min) produced log10 reductions of 2.50 and 1.71, equalling those of the reference procedure with n-propanol (2.49 and 1.78). When 'Hibisol' was used for 5 min rather than 4 min, a considerable, though not significant, increase in effect was achieved (log10 reductions of 2.90 and 2.07). Replacement of unmedicated soap by 'Hibiscrub' could significantly improve the effectiveness of the hand disinfection procedure commonly used by surgeons in German-speaking countries; namely to wash hands first with soap and then disinfect them with an alcoholic preparation. It may also be of additional advantage as this adds another 'layer' of CHX when 'Hibisol' rather than alcohol alone is used.     

The effect of disinfectants on perforated gloves.

Three types of gloves, 'Biogel', 'Regent Dispo Surgical' gloves and Ansell gammex were perforated, and contaminated with Escherichia coli or Pseudomonas aeruginosa as test organisms applied either to the hand or the glove surface. The glove surface was decontaminated with alcoholic chlorhexidine ('Hibisol'), methylated spirit, or soap and water. The experiments were performed in triplicate on three separate days. The experiments were designed to study the ability of the three disinfection methods to reduce the bacterial count of 10(6) colony forming units (cfu) ml-1 (applied to perforated gloves or hands) sufficiently to permit the re-use of such gloves for non-sterile ward procedures. The best method of disinfection was using alcoholic chlorhexidine which not only reduced glove surface carriage but also reduced transfer of bacteria to the hands through the perforation in the gloves. Soap and water was the least effective. Escherichia coli was more easily removed than P. aeruginosa. We recommend that non-sterile ward procedures may be carried out even after gloves have been perforated provided alcoholic chlorhexidine is used between each procedure to reduce cross-infection between patients.