Günter Kampf

How long do nosocomial pathogens persist on inanimate surfaces? A systematic review

BackgroundInanimate surfaces have often been described as the source for outbreaks of nosocomial infections. The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces.MethodsThe literature was systematically reviewed in MedLine without language restrictions. In addition, cited articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included.ResultsMost gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae, however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days. Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV type 1 and 2, have been shown to persist from only a few hours up to 7 days.ConclusionThe most common nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of transmission if no regular preventive surface disinfection is performed.

How irritant is alcohol

Summary Backgroundu2002 Alcohol‐based hand rubs are used worldwide to prevent transmission of nosocomial pathogens.

Hand Hygiene for the Prevention of Nosocomial Infections

BACKGROUNDnThe WHO regards hand hygiene as an essential tool for the prevention of nosocomial infection, but compliance in clinical practice is often low.nnnMETHODSnThe relevant scientific literature and national and international evidence-based recommendations (Robert Koch Institute [Germany], WHO) were evaluated.nnnRESULTSnHygienic hand disinfection has better antimicrobial efficacy than hand-washing and is the procedure of choice to be performed before and after manual contact with patients. The hands should be washed, rather than disinfected, only when they are visibly soiled. Skin irritation is quite common among healthcare workers and is mainly caused by water, soap, and prolonged wearing of gloves. Compliance can be improved by training, by placing hand-rub dispensers at the sites where they are needed, and by physicians setting a good example for others.nnnCONCLUSIONSnImproved compliance in hand hygiene, with proper use of alcohol-based hand rubs, can reduce the nosocomial infection rate by as much as 40%.

Effects of disinfectants and detergents on skin irritation

We investigated the biological response of regular human skin to alcohol‐based disinfectants and detergents in a repetitive test design. Using non‐invasive diagnostic tools such as transepidermal water loss, laser‐Doppler flowmetry and corneometry, we quantified the irritative effects of a propanol‐based hand disinfectant (Sterillium®), its propanol mixture (2‐propanol 45% w/w and 1‐propanol 30% w/w), sodium lauryl sulfate (SLS) 0.5% and distilled water. The substances were applied in a 2‐D patch test in a repetitive occlusive test design to the back. Additionally, we performed a wash test on the forearms that was supposed to mimic the skin affection in the normal daily routine of health care workers. In this controlled half‐side test design, we included the single application of the hand rub, SLS 0.5% and water as well as a tandem application of the same substances. Patch test and wash test showed similar results. The alcohol‐based test preparations showed minimal irritation rather comparable to the application of water. However, the detergent SLS produced stronger barrier disruption, erythema and dryness than the alcohol‐based preparations. There was no additional irritation at the combined use of SLS and disinfectants. By contrary, there was even a decrease in barrier disruption and erythema induced by the tandem application of SLS followed by alcohol‐based disinfection compared with the use of SLS alone. These findings show a less irritant effect of alcohol‐based disinfectants on the skin than detergents. Our study shows that there is no summation of irritating effects of a common detergent and propanol and that the combination of washing and disinfection has a rather protective aspect compared with washing alone.

Influence of rub-in technique on required application time and hand coverage in hygienic hand disinfection

BackgroundRecent data indicate that full efficacy of a hand rub preparation for hygienic hand disinfection can be achieved within 15 seconds (s). However, the efficacy test used for the European Norm (EN) 1500 samples only the fingertips. Therefore, we investigated hand coverage using sixteen different application variations. The hand rub was supplemented with a fluorescent dye, and hands were assessed under UV light by a blind test, before and after application. Fifteen non-healthcare workers were used as subjects for each application variation apart from one test which was done with a group of twenty healthcare workers. All tests apart from the reference procedure were performed using 3 mL of hand rub. The EN 1500 reference procedure, which consists of 6 specific rub-in steps performed twice with an aliquot of 3 ml each time, served as a control. In one part of this study, each of the six steps was performed from one to five times before proceeding to the next step. In another part of the study, the entire sequence of six steps was performed from one to five times. Finally, all subjects were instructed to cover both hands completely, irrespective of any specific steps (responsible application). Each rub-in technique was evaluated for untreated skin areas.ResultsThe reference procedure lasted on average 75 s and resulted in 53% of subjects with at least one untreated area on the hands. Five repetitions of the rub-in steps lasted on average 37 s with 67% of subjects having incompletely treated hands. One repetition lasted on average 17 s, and all subjects had at least one untreated area. Repeating the sequence of steps lasted longer, but did not yield a better result. Responsible application was quite fast, lasting 25 s among non-healthcare worker subjects and 28 s among healthcare workers. It was also effective, with 53% and 55% of hands being incompletely treated. New techniques were as fast and effective as responsible application. Large untreated areas were found only with short applications. Fingertips and palms were often covered completely.ConclusionIn clinical practice, hand disinfection is apparently better than practitioners of infection control often anticipate. Based on our data, a high-quality hygienic hand disinfection is not possible within 15 s. A 30 s application time can, however, be recommended for clinical practice. The currently recommended six steps of EN 1500 are not really suitable for clinical practice, because they yield comparably poor results. The most appropriate application procedure may be responsible application, or one of the other new techniques.

Effectiveness of alcohol-based hand disinfectants in a public administration: Impact on health and work performance related to acute respiratory symptoms and diarrhoea

BackgroundThe economical impact of absenteeism and reduced productivity due to acute infectious respiratory and gastrointestinal disease is normally not in the focus of surveillance systems and may therefore be underestimated. However, large community studies in Europe and USA have shown that communicable diseases have a great impact on morbidity and lead to millions of lost days at work, school and university each year. Hand disinfection is acknowledged as key element for infection control, but its effect in open, work place settings is unclear.MethodsOur study involved a prospective, controlled, intervention-control group design to assess the epidemiological and economical impact of alcohol-based hand disinfectants use at work place. Volunteers in public administrations in the municipality of the city of Greifswald were randomized in two groups. Participants in the intervention group were provided with alcoholic hand disinfection, the control group was unchanged. Respiratory and gastrointestinal symptoms and days of work were recorded based on a monthly questionnaire over one year. On the whole, 1230 person months were evaluated.ResultsHand disinfection reduced the number of episodes of illness for the majority of the registered symptoms. This effect became statistically significant for common cold (OR = 0.35 [0.17 - 0.71], p = 0.003), fever (OR = 0.38 [0.14-0.99], p = 0.035) and coughing (OR = 0.45 [0.22 - 0.91], p = 0.02). Participants in the intervention group reported less days ill for most symptoms assessed, e.g. colds (2.07 vs. 2.78%, p = 0.008), fever (0.25 vs. 0.31%, p = 0.037) and cough (1.85 vs. 2.00%, p = 0.024). For diarrhoea, the odds ratio for being absent became statistically significant too (0.11 (CI 0.01 - 0.93).ConclusionHand disinfection can easily be introduced and maintained outside clinical settings as part of the daily hand hygiene. Therefore it appears as an interesting, cost-efficient method within the scope of company health support programmes.Trial registration numberISRCTN: ISRCTN96340690

What is left to justify the use of chlorhexidine in hand hygiene

The CDC guideline for hand hygiene describes chlorhexidine gluconate as an agent with substantial residual activity. But not all studies support this claim. In both suspension tests (e.g. EN 13727) and tests under practical conditions (e.g. EN 1500) it is crucial to neutralize any residual activity in the sampling fluid in order to make sure that the agent does not continue to damage surviving cells after exposure. The neutralization step must also be validated. If this is not done the efficacy may be significantly overestimated, and the healthcare professional may rely on data which do not represent the true efficacy of an agent. A review of eight studies which are cited to support substantial residual activity show that none of them were performed with validated neutralization. Seven of them do not demonstrate any residual activity for chlorhexidine gluconate. Only in one study some residual activity is described but the validity of the study design does not allow make this claim as no neutralizing agents were used at all. The benefits of using an active agent must outweigh any risks in order to justify its use. If no real benefits are left for chlorhexidine gluconate in hand hygiene, all the risks count even more such as skin irritation, allergic reactions including anaphylactic shock, and acquired bacterial resistance. Unless there is new and valid evidence to clearly support a benefit of using chlorhexidine gluconate in hand hygiene, healthcare workers should prefer formulations without this agent.

Hand disinfection: How irritant are alcohols?

Irritant contact dermatitis is commonly found on hands of healthcare employees and is often explained by contact to water and detergents. Studies on the dermal tolerance clearly show that the degree of skin irritation is significantly lower after application of alcohol in comparison to detergents. It has also been shown in standardised wash tests using a foam roller that the application of alcohol or water immediately after a detergent-based wash can significantly decrease the degree of skin irritation, probably due to a wash-off of residual detergent. If evidence-based hand hygiene is taught early during nurses training it can substantially reduce irritant contact dermatitis supporting initiatives of primary prevention among healthcare employees. The irritant potential of commonly used alcohols in hand antiseptics is very low. If the skin is pre-irritated, e.g. by detergents or water, alcohols can cause a burning sensation which is, however, not an allergic reaction and does not further harm the skin. True allergic reactions to alcohols have so far not been confirmed. From the dermatological point of view the use of alcohols for hand hygiene has clear advantages over washing with water and detergents.

Suitability of Sterillium Gel™ for surgical hand disinfection

In some countries, alcohol-based hand gels are used for hygienic hand disinfection but their efficacy and suitability for surgical hand disinfection has never been investigated. The efficacy of Sterillium Gel was investigated according to prEN 12791 in two separate experiments. Finger tips of 20 volunteers per experiment were sampled for resident skin bacteria before surgical hand disinfection. In a cross-over design, each volunteer carried out a surgical hand disinfection with the reference alcohol [n-propanol 60%, (v/v)] or Sterillium Gel [ethanol 85% (v/v)] for 3 min. After the product application, one hand was sampled for the immediate effect, the other hand was gloved for 3 h and then sampled for the sustained effect. Samples were analysed for remaining resident bacteria. The mean of the pre-value, the 0 h and 3 h values of the reference disinfection and the test product were calculated. With the reference alcohol, respective mean immediate log10-reduction factors of 2.06+/-0.76 and 2.23+/-1.13 were found in both experiments. The mean sustained effects with the reference alcohol were 2.03+/-1.14 and 1.44+/-0.81. Sterillium Gel achieved respective mean immediate effects of 2.48+/-1.06 and 2.13+/-0.81, the mean sustained effects were 2.77+/-0.95 and 2.18+/-0.72. They proved significantly larger than those obtained with the reference alcohol (P<0.05; pair-wise Wilcoxon test). Sterillium Gel, therefore, more than fulfils the efficacy requirements for surgical hand disinfection of prEN 12791. In addition, 25 of 26 operating theatre healthcare workers in an orthopaedic hospital found it suitable for surgical hand disinfection after a single use, which included putting on a pair of surgical gloves. Although none of them had ever used an alcohol-based gel before, they had rather been accustomed to alcohol-based liquid products for years. The main reasons given for the positive assessment were better skin feeling after use, smell and easier donning of the surgical gloves. No significant correlation was found between overall or dermal acceptance and years of professional experience, profession or number of gel portions used for surgical hand disinfection (Pearsons correlation; P>0.05).

Efficacy of ethanol-based hand foams using clinically relevant amounts: a cross-over controlled study among healthy volunteers.

BackgroundFoams containing 62% ethanol are used for hand decontamination in many countries. A long drying time may reduce the compliance of healthcare workers in applying the recommended amount of foam. Therefore, we have investigated the correlation between the applied amount and drying time, and the bactericidal efficacy of ethanol foams.MethodsIn a first part of tests, four foams (Alcare plus, Avagard Foam, Bode test foam, Purell Instant Hand Sanitizer) containing 62% ethanol, which is commonly used in U.S. hospitals, were applied to 14 volunteers in a total of seven variations, to measure drying times. In a second part of tests, the efficacy of the established amount of foam for a 30 s application time of two foams (Alcare plus, Purell Instant Hand Sanitizer) and water was compared to the EN 1500 standard of 2 × 3 mL applications of 2-propanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each application used a cross-over design against the reference alcohol with 15 volunteers.ResultsThe mean weight of the applied foam varied between 1.78 and 3.09 g, and the mean duration to dryness was between 37 s and 103 s. The correlation between the amount of foam applied and time until hands felt dry was highly significant (p < 0.001; Pearsons correlation coefficient: 0.724; 95% confidence interval: 0.52-0.93). By linear correlation, 1.6 g gave an intercept of a 30 s application time. Application of 1.6 g of Purell Instant Hand Sanitizer (mean log10-reduction: 3.05 ± 0.45) and Alcare plus (3.58 ± 0.71) was significantly less effective than the reference disinfection (4.83 ± 0.89 and 4.60 ± 0.59, respectively; p < 0.001). Application of 1.6 g of water gave a mean log10-reduction of 2.39 ± 0.57.ConclusionsWhen using 62% ethanol foams, the time required for dryness often exceeds the recommended 30 s. Therefore, only a small volume is likely to be applied in clinical practice. Small amounts, however, failed to meet the efficacy requirements of EN 1500 and were only somewhat more effective than water.