Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs

Biometric fingerprinting for visa application: device and procedure are risk factors for infection transmission

BACKGROUND

Biometric fingerprint identity verification is currently introduced in visa application and entry screening at border control. The system implies physical contact between the skin and the surface of the fingerprint-capturing and reading devices.

AIM

To assess the risk of infection transmission through fingerprinting.

METHODS

The medical literature was reviewed for the potential of microorganisms to be carried on the skin of hands in the community, to be transferred from hands to inanimate surfaces, to survive on surfaces, and to be transferred in doses exceeding the infectious dose. The fingerprinting procedures as currently applied were reviewed.

RESULTS

Factors that favor transfer of microorganisms are large skin-surface contact between flat fingers (2 x 20 cm(2)) and fingerprint-capturing device, nonporous contact surface, large overlap of contact surface and short turnaround time between successive applicants, high contact pressure, and difficulties to disinfect devices. Transmission risk exists for enteric viruses (rotavirus, norovirus, and hepatitis A virus), respiratory viruses (respiratory syncytial virus, rhinovirus, influenza virus, etc.), and enteropathogenic bacteria with low infectious doses (Shigella dysenteriae, Enterohemorrhagic Escherichia coli, etc.). Using Monte Carlo risk analysis on US data, transmission of human rotavirus is estimated at 191 [95% credible intervals (CI) 0-289] per million fingerprint-capturing procedures. Application of 70% isopropyl hand rub and 85% ethanol hand gel reduces the risk to 77 (95% CI 0-118) and 0.3 (95% CI 0-0.3) transmissions per million procedures, respectively.

CONCLUSIONS

The fingerprinting procedure as currently used is associated with a risk of infection transmission. Simple hygienic measures can considerably reduce this transmission risk.

Prevention of hospital-acquired infections: review of non-pharmacological interventions

Hospital-acquired (nosocomial) infections (HAIs) increase morbidity, mortality and medical costs. In the USA alone, nosocomial infections cause about 1.7 million infections and 99 000 deaths per year. HAIs are spread by numerous routes including surfaces (especially hands), air, water, intravenous routes, oral routes and through surgery. Interventions such as proper hand and surface cleaning, better nutrition, sufficient numbers of nurses, better ventilator management, use of coated urinary and central venous catheters and use of high-efficiency particulate air (HEPA) filters have all been associated with significantly lower nosocomial infection rates. Multiple infection control techniques and strategies simultaneously ('bundling') may offer the best opportunity to reduce the morbidity and mortality toll of HAIs. Most of these infection control strategies will more than pay for themselves by saving the medical costs associated with nosocomial infections. Many non-pharmacological interventions to prevent many HAIs will also reduce the need for long or multiple-drug antibiotic courses for patients. Lower antibiotic drug usage will reduce risk of antibiotic-resistant organisms and should improve efficacy of antibiotics given to patients who do acquire infections.

Bacterial population kinetics on hands during 2 consecutive surgical hand disinfection procedures

BACKGROUND

Although consecutive surgical hand disinfections is common clinical practice, the effect on the bacterial density on hands has not been studied for all commonly used hand rubs. We studied the effect of 2 consecutive applications of hand rubs on resident bacterial hand flora.

METHODS

A propanol-based hand rub (PBHR; Sterillium) and the reference alcohol (60% n-propanol) were tested in a Latin-square design according to EN 12791. The first application of the PBHR was always for 1.5 minutes; the second application was for 1.5, 1, or 0.5 minutes. The reference alcohol was always applied for 3 minutes. Pre-values and post-values were obtained in accordance with EN 12791.

RESULTS

The first reference disinfection reduced the bacterial density by 2.87 log(10) (immediate efficacy) and 2.27 log(10) (after 3 hours). The PBHR yielded a similar reduction. Immediately after the second reference disinfection, bacterial density was reduced by 0.45 log(10). Application of the PBHR yielded greater reductions of 0.71 log(10) (after 0.5 minute), 0.79 log(10) (after 1 minute), and 1.12 log(10) (after 1.5 minutes). The difference between all treatments was not significant (P = .089; Friedman test). After 3 hours, bacterial density was further decreased by 1.11 log(10) (reference disinfection), 1.89 log(10) (PBHR, 1 minute), 1.67 log(10) (PBHR, 1.5 minutes), and 1.08 log(10) (PBHR, 0.5 minute). The difference between all treatments was significant (P = .005), but none of the short treatments with the PBHR was significantly less effective than the reference treatment (P > .05; Wilcoxon-Wilcox test).

CONCLUSIONS

Overall, a simple 1.5-minute application of a well-formulated PBHR for surgical hand disinfection keeps the bacterial density as low as possible ("irreducible minimum") even in 2 consecutive surgical procedures of 3 hours.

How effective are hand antiseptics for the postcontamination treatment of hands when used as recommended?

BACKGROUND

Alcohol-based hand antiseptics are often tested using 3 or 5 mL per application, but smaller volumes are likely to be applied in clinical practice. For that reason, we investigated the efficacy of 2 different volumes of 4 marketed hand rubs when applied to contaminated hands.

METHODS

Hands of 16 volunteers were contaminated with Serratia marcescens. Hand rub A (85% ethanol), hand rub B (60% ethanol), hand rub C (62% ethanol), and hand rub D (61% ethanol) were applied as blinded formulations, each in single applications of 2.4 or 3.6 mL. Hibiclens (4% chlorhexidine gluconate) served as the reference treatment. Each hand rub was rubbed into the hands until dry. Preintervention and postintervention bacterial populations were obtained by the glove juice method. Neutralization of residual activity was validated.

RESULTS

A 2.4-mL aliquot of a hand rub product was sufficient to cover both hands in 96.9% of the subjects. Applied in that volume, hand rubs produced a log(10)-reduction in bacterial populations of 2.79 for hand rub A, 2.26 for hand rub C, 1.96 for hand rub D, and 1.90 for hand rub B. Application of 3.6 mL was significantly more effective for hand rubs B, C, and D. The reference treatment reduced test bacteria by 2.39 log(10). Analysis of variance revealed that both the type of hand rub and the applied volume had a highly significant influence on the mean log(10) reduction on artificially contaminated hands (P < .001).

CONCLUSIONS

Hand rubs applied in amounts sufficient to cover both hands may not reduce the bacterial density by even 2 log(10) steps. Based on our findings, the general trend toward alcohol-based hand rubs should not overlook evidence of significant differences in efficacy that appear to be related primarily to a product's overall concentration of alcohol.

Urinary concentrations of triclosan in the U.S. population: 2003-2004

BACKGROUND

Triclosan is a synthetic chemical with broad antimicrobial activity that has been used extensively in consumer products, including personal care products, textiles, and plastic kitchenware.

OBJECTIVES

This study was designed to assess exposure to triclosan in a representative sample > or = 6 years of age of the U.S. general population from the 2003-2004 National Health and Nutrition Examination Survey (NHANES).

METHODS

We analyzed 2,517 urine samples using automated solid-phase extraction coupled to isotope dilution-high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

We detected concentrations of total (free plus conjugated) triclosan in 74.6% of samples at concentrations of 2.4-3,790 microg/L. The geometric mean and 95th percentile concentrations were 13.0 microg/L (12.7 microg/g creatinine) and 459.0 microg/L (363.8 mug/g creatinine), respectively. We observed a curvilinear relation between age and adjusted least square geometric mean (LSGM) concentrations of triclosan. LSGM concentrations of triclosan were higher in people in the high household income than in people in low (p < 0.01) and medium (p = 0.04) income categories.

CONCLUSIONS

In about three-quarters of urine samples analyzed as part of NHANES 2003-2004, we detected concentrations of triclosan. Concentrations differed by age and socioeconomic status but not by race/ethnicity and sex. Specifically, the concentrations of triclosan appeared to be highest during the third decade of life and among people with the highest household incomes.

Comprehensive bactericidal activity of an ethanol-based hand gel in 15 seconds

BACKGROUND

Some studies indicate that the commonly recommended 30 s application time for the post contamination treatment of hands may not be necessary as the same effect may be achieved with some formulations in a shorter application time such as 15 s.

METHOD

We evaluated the bactericidal activity of an ethanol-based hand gel (Sterillium Comfort Gel) within 15 s in a time-kill-test against 11 Gram-positive, 16 Gram-negative bacteria and 11 emerging bacterial pathogens. Each strain was evaluated in quadruplicate.

RESULTS

The hand gel (85% ethanol, w/w) was found to reduce all 11 Gram-positive and all 16 Gram-negative bacteria by more than 5 log10 steps within 15 s, not only against the ATCC test strains but also against corresponding clinical isolates. In addition, a log10 reduction > 5 was observed against all tested emerging bacterial pathogens.

CONCLUSION

The ethanol-based hand gel was found to have a broad spectrum of bactericidal activity in only 15 s which includes the most common species causing nosocomial infections and the relevant emerging pathogens. Future research will hopefully help to find out if a shorter application time for the post contamination treatment of hands provides more benefits or more risks.

A review of current strategies to reduce intraoperative bacterial contamination of surgical wounds

Surgical site infections are a mean topic in cardiac surgery, leading to a prolonged hospitalization, and substantially increased morbidity and mortality. One source of pathogens is the endogenous flora of the patient's skin, which can contaminate the surgical site. A number of preoperative skin care strategies are performed to reduce bacterial contamination like preoperative antiseptic showering, hair removal, antisepsis of the skin, adhesive barrier drapes, and antimicrobial prophylaxis. Furthermore we can also support the natural host defense by optimal intra-operative management of oxygen supply, normoglycemia, and temperature. Nevertheless we still have a number of patients, who develop a surgical site infection. Therefore new skin care strategies are introduced to reduce the contamination by the endogenous skin flora. We present the use of a new microbial sealant, InteguSeal((R)), which was evaluated in patients undergoing cardiac surgery. The preliminary results of this investigation showed a trend in surgical site infection reduction by the use of this new microbial sealant.

Low concentrations of commercial alcohol hand rubs facilitate growth of and secretion of extracellular proteins by multidrug-resistant strains of Acinetobacter baumannii

Acinetobacter baumannii is increasingly recognized as an important multidrug-resistant nosocomial pathogen. Recent work has highlighted enhanced growth and heightened virulence in the presence of ethyl alcohols. As alcohol-based hand rubs (ABHRs) are extensively used in health care settings, the authors set out to determine whether the hand rubs could also influence the growth of prevalent multidrug-resistant strains circulating in UK hospitals. A significant increase in growth was observed when minimal media were supplemented with concentrations of 1 % and lower of four commercially available hand rubs. In addition, growth in ABHR-supplemented media resulted in secretion of proteins into the culture supernatant. One of these was identified as OmpA, which is recognized as having emulsifying activity, which could potentially confer enhanced pathogenicity to A. baumannii.

Outbreak of human metapneumovirus infection in psychiatric inpatients: implications for directly observed use of alcohol hand rub in prevention of nosocomial outbreaks

Nosocomial outbreaks of infectious diseases in psychiatric facilities are not uncommon but the implementation of infection control measures is often difficult. Here, we report an outbreak of an acute respiratory illness in a psychiatric ward between 29 July and 20 August 2005 involving 31 patients. Human metapneumovirus was detected in seven (23%) patients by reverse transcription-polymerase chain reaction and nucleotide sequencing. A review of outbreak surveillance records showed that six nosocomial outbreaks occurred in the year 2005, of which four (67%) were confirmed or presumably related to a respiratory viral infection. Directly observed deliveries of alcohol hand rub 4-hourly during daytime to all psychiatric patients was instituted in December 2005. Only one nosocomial respiratory viral outbreak occurred in the following year. The total number of patients and staff involved in nosocomial outbreaks due to presumed or proven respiratory virus infections decreased significantly from 60 to six (P<0.001), whereas those due to all types of nosocomial outbreaks also decreased from 70 to 24 (P=0.004). Alcohol hand rub has been shown to have potent bactericidal and virucidal activity against a wide range of nosocomial pathogens. Regular use of directly observed alcohol hand rub may decrease the incidence and scale of nosocomial outbreaks due to enveloped respiratory viruses especially in mentally incapacitated patients.

Biocidal textiles can help fight nosocomial infections

The rates of nosocomial infections, especially by those caused by antibiotic resistant bacteria, are increasing alarmingly over the globe. Although more rigorous infection control measures are being implemented, it is clear that the current modalities to reduce nosocomial infections are not sufficient. Textiles are an excellent substrate for bacterial growth under appropriate moisture and temperature conditions. Patients shed bacteria and contaminate their pyjamas and sheets. The temperature and humidity between the patients and the bed are appropriate conditions allowing for effective bacterial proliferation. Several studies have found that personnel in contact with contaminated textiles were the source of transmission of the micro-organisms to susceptible patients. Furthermore, it has been reported that bed making in hospitals releases large quantities of micro-organisms into the air, which contaminate the immediate and non-immediate surroundings. Contaminated textiles in hospitals can thus be an important source of microbes contributing to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. We hypothesize that the use of antimicrobial textiles, especially in those textiles that are in close contact with the patients, may significantly reduce bioburden in clinical settings and consequently reduce the risk of nosocomial infections. These textiles should possess broad spectrum biocidal properties. They should be safe for use and highly effective against antibiotic resistant micro-organisms, including those that are commonly involved in hospital-acquired infections, and they should not permit the development of resistant micro-organisms to the active compound.

Consumer antibacterial soaps: effective or just risky?

BACKGROUND

Much has been written recently about the potential hazards versus benefits of antibacterial (biocide)-containing soaps. The purpose of this systematic literature review was to assess the studies that have examined the efficacy of products containing triclosan, compared with that of plain soap, in the community setting, as well as to evaluate findings that address potential hazards of this use--namely, the emergence of antibiotic-resistant bacteria.

METHODS

The PubMed database was searched for English-language articles, using relevant keyword combinations for articles published between 1980 and 2006. Twenty-seven studies were eventually identified as being relevant to the review.

RESULTS

Soaps containing triclosan within the range of concentrations commonly used in the community setting (0.1%-0.45% wt/vol) were no more effective than plain soap at preventing infectious illness symptoms and reducing bacterial levels on the hands. Several laboratory studies demonstrated evidence of triclosan-adapted cross-resistance to antibiotics among different species of bacteria.

CONCLUSIONS

The lack of an additional health benefit associated with the use of triclosan-containing consumer soaps over regular soap, coupled with laboratory data demonstrating a potential risk of selecting for drug resistance, warrants further evaluation by governmental regulators regarding antibacterial product claims and advertising. Further studies of this issue are encouraged.

Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans

Background

Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans.

Methods

Twelve volunteers applied three hand-rubs containing 95% (hand-rub A), 85% (hand-rub B) and 55% ethanol (hand-rub C; all w/w). For hygienic hand disinfection, 4 mL were applied 20 times for 30 s, with 1 minute break between applications. For surgical hand disinfection, 20 mL of each hand rub was applied to hands and arms up to the level of the elbow 10 times for 3 minutes, with a break of 5 minutes between applications. Blood concentrations of ethanol and acetaldehyde were determined immediately prior and up to 90 minutes after application using head space gas chromatography.

Results

The median of absorbed ethanol after hygienic hand disinfection was 1365 mg (A), 630 mg (B), and 358 mg (C). The proportion of absorbed ethanol was 2.3% (A), 1.1% (B), and 0.9% (C). After surgical hand disinfection, the median of absorbed ethanol was 1067 mg (A), 1542 mg (B), and 477 mg (C). The proportion of absorbed ethanol was 0.7% (A), 1.1% (B), and 0.5% (C). The highest median acetaldehyde concentration after 20 hygienic hand disinfections was 0.57 mg/L (hand-rub C, after 30 min), after 10 surgical hand disinfections 3.99 mg/L (hand-rub A, after 20 minutes).

Conclusion

The overall dermal and pulmonary absorption of ethanol was below toxic levels in humans and allows the conclusion that the use of the evaluated ethanol-based hand-rubs is safe.

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.

How irritant is alcohol?

BACKGROUND

Alcohol-based hand rubs are used worldwide to prevent transmission of nosocomial pathogens.

OBJECTIVES

To investigate skin irritation caused by alcohols alone and in combination with detergent washing.

METHODS

Single and repetitive patch testing with 60-100% alcohols [ethanol, 1-propanol, 2-propanol (synonyms: isopropyl alcohol, isopropanol)], a positive control [0.5% sodium lauryl sulphate (SLS)] and negative controls (empty chamber and water) were performed. Wash tests were performed with 80% ethanol and 0.5% SLS on the forearms with each agent alone and with both agents in a tandem design. Skin hydration, erythema and barrier disruption [measured as transepidermal water loss (TEWL)] were evaluated (always 15 volunteers).

RESULTS

We found no significant change in skin barrier or erythema induced by the alcohols in the patch tests, whereas skin hydration decreased significantly. Application of alcohols to previously irritated skin did not show a stronger skin barrier disruption than application of SLS alone. Wash tests demonstrated that alcohol application caused significantly less skin irritation than washing with a detergent (TEWL, P < 0.001; skin hydration, P < 0.05; erythema, P < 0.05). Even on previously irritated skin, ethanol did not enhance irritation. By contrast, a protective effect of ethanol used after skin washing was observed (TEWL, P < 0.05; skin hydration, P < 0.05; erythema, P < 0.05).

CONCLUSIONS

Alcohol-based hand rubs cause less skin irritation than hand washing and are therefore preferred for hand hygiene from the dermatological point of view. An alcohol-based hand rub may even decrease rather than increase skin irritation after a hand wash due to a mechanical partial elimination of the detergent.

Infection control: worlds apart primary and secondary care

Healthcare associated infection continues to be a major cause of morbidity and mortality in healthcare. The fact that most of what has been written on the subject of infection control and prevention relates to the hospital setting is perhaps understandable given the proximity and immune status of patients in secondary care. However, the change of term from hospital-acquired infection to healthcare-associated infection acknowledges that a similar burden may exist in community settings. Influential reports suggest that community infection control is ill-defined and there is ongoing debate whether community-based infection control nursing involves the same or different approaches to hospital infection nursing. This paper explores some of the differences between infection control practice in primary and secondary care and examines the reasons for this.

Comparison of the antibacterial efficacy and acceptability of an alcohol-based hand rinse with two alcohol-based hand gels during routine patient care

The aims of this study were to compare the antibacterial efficacy of handrubbing with an alcoholic rinse (AHRR) and two different alcoholic gels (AHRG) in reducing hand contamination under practical use conditions. We wanted to assess the acceptability of the three products and to determine the effect of each product on overall hand hygiene compliance. A prospective alternating time-series clinical trial was performed in a medical intensive care unit. The study was divided into three six-week periods (P1, P2, P3). Handrubbing was achieved with Sterillium rinse (AHRR) during P1, sterillium gel(AHRG-1) during P2 and Manugel Plus (AHRG-2) during P3. Pre- and post-rubbing hand contaminations were assessed immediately after a direct contact with a patient, using the glove juice technique. Health care workers (HCWs) evaluated the acceptability of the products through a self-administered anonymous questionnaire. Compliance of HCWs with hand hygiene was assessed during the three periods. We studied 242 handrubbing opportunities. The mean reduction factor (expressed as the Log(10) CFU/mL) of the AHRR, AHRG-1 and AHRG-2 were 1.28+/-0.95, 1.29+/-0.84 and 0.51+/-0.73, respectively (p<0.001). Assessment of the three products by HCWs indicated that AHRR and AHRG-1 were significantly better accepted than AHRG-2. The overall compliance of HCWs to hand hygiene was better when gel was available. Under practical use conditions, AHRG-1 and AHRR were more effective than AHRG-2, although all were claimed to pass the European standard EN1500. In vivo trials are essential to compare the antimicrobial efficacy of products for handrubbing.

Formation of chloroform and other chlorinated byproducts by chlorination of triclosan-containing antibacterial products

Triclosan is a widely used antibacterial agent found in many personal hygiene products. Although it has previously been established that pure triclosan and free chlorine readily react, interactions between triclosan-containing consumer products and free chlorine have not previously been analyzed in great depth. Sixteen double-blinded solutions including both triclosan-containing (1.14-3.12 mg triclosan/g product) and triclosan-free products were contacted with free chlorine at pH 7. Products detected included (chlorophenoxy) phenols, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and chloroform. The daughter product yields were found to be highly variable and were dependent on the antimicrobial product investigated, the free chlorine to triclosan ratio, and the temperature at which the study was conducted. Lowering the temperature from 40 to 30 degrees C resulted in a decreased average chloroform yield from 0.50 to 0.37 mol chloroform/mol triclosan consumed after 1 min of reaction time for an initial free chlorine concentration of 4.0 mg/L as Cl2. At 40 degrees C the average molar chloroform yields decreased to 0.29 and <0.1 when the initial free chlorine concentration was decreased to either 2.0 or 1.0 mg/L as Cl2, respectively. Field experiments, in which Atlanta, GA and Danville, VA tap waters were augmented with various soap products, exhibited results varying from the laboratory experiments in that different productyields were observed. These differences are attributed to the chlorine demand of constituents in the tap water. A simple exposure model suggests that exposure to chloroform can be significant under some conditions.

Suitability of vaccinia virus and bovine viral diarrhea virus (BVDV) for determining activities of three commonly-used alcohol-based hand rubs against enveloped viruses

BACKGROUND

A procedure for including activity against enveloped viruses in the post-contamination treatment of hands has been recommended, but so far no European standard is available to implement it. In 2004, the German Robert Koch-Institute (RKI) and the German Association for the Control of Virus Disease (DVV) suggested that vaccinia virus and bovine viral diarrhea virus (BVDV) should be used as test viruses in a quantitative suspension test to determine the activity of a disinfectant against all enveloped viruses.

METHODS

We have studied the activities of three commonly-used alcohol-based hand rubs (hand rub A, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate; hand rub B, based on 80% ethanol; hand rub C, based on 95% ethanol) against vaccinia virus and BVDV, and in addition against four other clinically relevant enveloped viruses: herpes simplex virus (HSV) types 1 and 2, and human and avian influenza A virus. The hand rubs were challenged with different organic loads at exposure time of 15, 30 and 60 s. According to the guidelines of both BGA/RKI and DVV, and EN 14476:2005, the reduction of infectivity of each test virus was measured on appropriate cell lines using a quantitative suspension test.

RESULTS

All three alcohol-based hand rubs reduced the infectivity of vaccinia virus and BVDV by > or = 4 log10-steps within 15 s, irrespective of the type of organic load. Similar reductions of infectivity were seen against the other four enveloped viruses within 15 s in the presence of different types of organic load.

CONCLUSION

Commonly used alcohol-based hand rubs with a total alcohol concentration > or = 75% can be assumed to be active against clinically relevant enveloped viruses if they effectively reduce the infectivities of vaccinia virus and BVDV in a quantitative suspension test.

A statistical method for estimating the proportion of cases resulting from cross-transmission of multi-resistant pathogens in an intensive care unit

Multi-resistant bacteria are an increasing challenge for infection control in hospitals and the proportion of patients newly colonized with multi-resistant bacteria during their hospital stay can be used to assess the effectiveness of infection control measures. Current laboratory methods for estimating this require expensive additional tests. We propose an alternative statistical method to estimate the proportion of cases resulting from transmission in a hospital from the distribution of time intervals between subsequent cases. A prerequisite for the application of this method is the existence of records from regular screening of the patients during their hospital stay, usually performed in intensive care units (ICUs). We describe the method and present an example of its application using records of two multi-resistant pathogens collected in an ICU over a three-year period. The estimated proportion of cases resulting from transmission was 0.73 (95% CI: 0.56-0.90) for meticillin-resistant Staphylococcus aureus and 0.45 (95% CI 0.15-0.75) for imipenem-resistant Pseudomonas aeruginosa. The method proposed here can be used for retrospective evaluation of clinical records in order to evaluate the effectiveness of infection control measures in low endemicity settings.

Physician handwashing: what do parents want?

Transmission of micro-organisms from the hands of healthcare workers to patients is a major cause of healthcare-acquired infections. In 2002, the US Centers for Disease Control and Prevention (CDC) published guidelines for healthcare workers that included the recommendation for alcohol-based hand rub for hand hygiene during patient visits. In this prospective study we surveyed parental and healthcare workers' preferences for the hand hygiene practices of emergency physicians. The study comprised 99 parents of ill or injured children presenting to our emergency department and 100 healthcare providers (64 nurses, 29 physicians and seven nurse practitioners) within the department. There was a clear and similar preference by parents and healthcare workers for hand hygiene using soap and water over alcohol cleansing rubs. Furthermore, both groups preferred hand hygiene before and after the examination and wanted to observe the physician perform this procedure. In conclusion, families and healthcare worker preferences for hand hygiene are not in keeping with recommendations published by the CDC. Educational interventions are needed to disseminate the CDC's guidelines and to promote compliance with evidence-based recommendations for hand hygiene.

Visible-light-induced bactericidal activity of a nitrogen-doped titanium photocatalyst against human pathogens

The antibacterial activity of photocatalytic titanium dioxide (TiO(2)) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO(2) substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO(2) substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO(2) and carbon-doped TiO(2) substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO(2) substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO(2) substrates than by pure TiO(2) substrates. These findings suggest that nitrogen-doped TiO(2) has potential application in the development of alternative disinfectants for environmental and medical usages.

Skin condition associated with intensive use of alcoholic gels for hand disinfection: a combination of biophysical and sensorial data

Although hand hygiene is an important and inexpensive measure to prevent nosocomial infections in clinical settings, the compliance of healthcare workers remains low. In Europe, alcoholic hand disinfection is first choice, but there exists a limited user acceptability due to estimated adverse effects on skin condition. This study was designed to investigate skin tolerance to alcohol-based disinfecting gels and changes in skin condition depending on humectant concentration, alcohol grades, as well as type of alcohol used. A comparison of 6 alcohol-based gels was made based on a randomized double-blind study under in use conditions for 1 day. Skin condition was evaluated by measuring transepidermal water loss (TEWL), stratum corneum hydration, apparent skin pH, redness and degree of scaliness. With respect to user acceptability, all gels were sensorially evaluated using a questionnaire. We saw that none of the alcohol-based gels, applied under in use conditions, altered TEWL or caused irritation. All gels hydrated the skin, proportionally to their glycerine content, and decreased skin pH. Elevated ethanol concentrations resulted in increased scaliness. Sensorial assessment revealed less appreciation for isopropanol. From this study, it was concluded that gels containing an elevated glycerine concentration and 70% (v/v) ethanol are preferred.

An evaluation of patient area cleaning in 3 hospitals using a novel targeting methodology

BACKGROUND

Although environmental cleaning and disinfecting practices have become a cornerstone of patient care, assessment of actual compliance with such procedures has not been reported. Using a novel methodology, we developed a means to monitor directly such activities.

METHODS

A nontoxic target solution, which intensely fluoresces with a black light, was formulated to be inconspicuous yet readily removed by housekeeping products. Small volumes of material were confidentially applied to 12 target sites in patient rooms in 3 hospitals following terminal cleaning. The targets were reevaluated following terminal cleaning after several patients had occupied the room.

RESULTS

One hundred fifty-seven rooms and 1404 targets were evaluated. In the 3 hospitals studied, only 45%, 42%, and 56% of targets were removed by routine terminal cleaning/disinfecting activities. The frequency with which various individual sites were cleaned varied widely but was similar in all hospitals.

CONCLUSION

The use of a novel target compound to evaluate housekeeping practices confirmed high rates of cleaning of traditional sites but poor cleaning of many sites that have significant potential for harboring and transmitting microbial pathogens. This methodology has the potential for being used to evaluate objectively the cleaning/disinfecting activities in various health care settings.

Alcohol dehydrogenase restricts the ability of the pathogen Candida albicans to form a biofilm on catheter surfaces through an ethanol-based mechanism

Candida biofilms formed on indwelling medical devices are increasingly associated with severe infections. In this study, we used proteomics and Western and Northern blotting analyses to demonstrate that alcohol dehydrogenase (ADH) is downregulated in Candida biofilms. Disruption of ADH1 significantly (P = 0.0046) enhanced the ability of Candida albicans to form biofilm. Confocal scanning laser microscopy showed that the adh1 mutant formed thicker biofilm than the parent strain (210 microm and 140 microm, respectively). These observations were extended to an engineered human oral mucosa and an in vivo rat model of catheter-associated biofilm. Inhibition of Candida ADH enzyme using disulfiram and 4-methylpyrazole resulted in thicker biofilm (P < 0.05). Moreover, biofilms formed by the adh1 mutant strain produced significantly smaller amounts of ethanol, but larger amounts of acetaldehyde, than biofilms formed by the parent and revertant strains (P < 0.0001), demonstrating that the effect of Adh1p on biofilm formation is mediated by its enzymatic activity. Furthermore, we found that 10% ethanol significantly inhibited biofilm formation in vitro, with complete inhibition of biofilm formation at ethanol concentrations of >/=20%. Similarly, using a clinically relevant rabbit model of catheter-associated biofilm, we found that ethanol treatment inhibited biofilm formation by C. albicans in vivo (P < 0.05) but not by Staphylococcus spp. (P > 0.05), indicating that ethanol specifically inhibits Candida biofilm formation. Taken together, our studies revealed that Adh1p contributes to the ability of C. albicans to form biofilms in vitro and in vivo and that the protein restricts biofilm formation through an ethanol-dependent mechanism. These results are clinically relevant and may suggest novel antibiofilm treatment strategies.

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

BACKGROUND

Inanimate 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.

METHODS

The 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.

RESULTS

Most 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.

CONCLUSION

The 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.

Does a preceding hand wash and drying time after surgical hand disinfection influence the efficacy of a propanol-based hand rub?

Background

Recently, a propanol-based hand rub has been described to exceed the efficacy requirements of the European standard EN 12791 in only 1.5 min significantly. But the effect of a 1 min preceding hand wash and the effect of one additional minute for evaporation of the alcohol after its application on the efficacy after a 1.5 min application time has never been studied.

Methods

We have investigated a propanol-based hand rub (Sterillium^®, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate) in three variations: with (A) and without (B) a 1 min hand wash before the disinfection of 1.5 min with immediate sampling after the disinfection; and (C) without a hand wash before the disinfection but with sampling 1 min after the disinfection. The efficacy of the three variations was compared to the reference treatment of EN 12791. All experiments were performed in a Latin-square design with 20 volunteers. Pre- and post-values (immediate and after 3 hr) were obtained according to EN 12791.

Results

The 3 min reference disinfection reduced resident hand bacteria on average by 1.8 log₁₀ steps (immediate effect) and 1.4 log₁₀-steps (sustained effect) respectively. Method A was equally effective as the reference (immediate efficacy: 1.5 log₁₀-steps; sustained efficacy: 1.6 log₁₀-steps). Method B seemed to be more effective (immediate efficacy: 2.3 log₁₀-steps; sustained efficacy: 1.7 log₁₀-steps). Method C revealed the best efficacy (immediate efficacy: 2.3 log₁₀-steps; sustained efficacy: 2.0 log₁₀-steps). A comparison of all three treatment variations and the reference treatment revealed a significant difference for the immediate efficacy (p = 0.026; Friedman test), but not for the sustained efficacy (p = 0.430). A post-hoc-test for the immediate efficacy indicated a significant difference between methods A and C (p < 0.05; Wilcoxon-Wilcox test). Hence, none of the treatment variations was significantly less effective than the reference treatment.

Conclusion

An application of the propanol-based hand rub for 1.5 min after 1 min hand wash fulfills the efficacy requirements of EN 12791. The efficacy can be improved to some extent by omitting the preceding hand wash and by awaiting the evaporation of the alcohol which is clinical practice anyway. The preceding hand wash has the most negative effect on the immediate effect. Based on our data hands should not be routinely washed before the disinfection period unless there is a good reason for it such as visible soiling.

Evaluation of two methods of determining the efficacies of two alcohol-based hand rubs for surgical hand antisepsis

The antimicrobial efficacies of preparations for surgical hand antisepsis can be determined according to a European standard (prEN 12791 [EN]) and a U.S. standard (tentative final monograph for health care antiseptic drug products [TFM]). The U.S. method differs in the product application mode (hands and lower forearms, versus hands only in EN), the number of applications (11 over 5 days, versus a single application in EN), the sampling times (0, 3, and 6 h after application, versus 0 and 3 h in EN), the sampling methods (glove juice versus fingertip sampling in EN), and the outcome requirements (absolute bacterial reduction factor [RF], versus noninferiority to reference treatment in EN). We have studied the efficacies of two hand rubs according to both methods. One hand rub was based on 80% ethanol and applied for 2 min, and the other one was based on 45% propan-2-ol, 30% propan-1-ol, and 0.2% mecetronium etilsulfate and applied for 1.5 min. The ethanol-based hand rub was equally effective as the 3-min reference disinfection of prEN 12791 in both the immediate (RFs, 2.97 +/- 0.89 versus 2.92 +/- 1.03, respectively) and sustained (RFs, 2.20 +/- 1.07 versus 2.47 +/- 1.25, respectively) effects. According to TFM, the immediate effects were 2.99 log10 (day 1), 3.00 log10 (day 2), and 3.43 log10 (day 5), and bacterial counts were still below baseline after 6 h. The propanol-based hand rub was even more effective than the reference disinfection of prEN 12791 in both the immediate (RFs, 2.35 +/- 0.99 versus 1.86 +/- 0.87, respectively) and sustained (RFs, 2.17 +/- 1.00 versus 1.50 +/- 1.26, respectively) effects. According to TFM, the immediate effects were 2.82 log10 (day 1), 3.29 log10 (day 2), and 3.25 log10 (day 5), and bacterial counts were still below baseline after 6 h. Some formulations have been reported to meet the efficacy requirements of one of the methods but not those of the other. That is why we conclude that, despite our results, meeting the efficacy requirements of one test method does not allow the claim that the requirements of the other test method are also met.

Effect of a 1min hand wash on the bactericidal efficacy of consecutive surgical hand disinfection with standard alcohols and on skin hydration

BACKGROUND

In most surgical theatres, a 1 min or even longer hand wash is routine as part of the pre-operative hand disinfection. But its benefit has recently been seen critically.

METHODS

We have therefore investigated the effect of a 1 min hand wash on skin hydration and on the efficacy of consecutive surgical hand rubbing with three standard alcohols (60% propan-1-ol, 60% propan-2-ol, 80% ethanol; all v/v) on the resident hand flora. Three types of treatment were performed: (i) a 1 min pre-wash before surgical hand disinfection, (ii) no pre-wash before surgical hand disinfection and (iii) no pre-wash but use of a brush for 1 min during disinfection procedure. The efficacy of the alcohols was determined according to prEN 12791 with the same 20 volunteers in paired groups. To assess the effect of the hand wash on skin hydration, 10 volunteers washed their hands with sapo kalinus for 1 min and dried hands with a paper towel. Skin hydration was measured with a corneometer before the hand wash and subsequently up to 10 min thereafter both on the palm and dorsum of hands. We also tested the reduction of bacterial spores by a 15 s hand wash according to EN 1499 after artificial contamination of hands of 14 volunteers with spores of B. stearothermophilus.

RESULTS

Propan-1-ol (60%) was most effective with a mean log10 reduction of 2.11, followed by ethanol (80%) with a mean log10 reduction of 1.76 and propan-2-ol (60%) with a mean log10 reduction of 0.57 (all immediate effect without hand wash). The efficacy of the alcohols was neither significantly improved nor impaired by a preceding 1 min hand wash, but there is a trend towards better efficacy on dry hands. Using a brush for 1 min during disinfection resulted in a better efficacy with all alcohols. An anaylsis of variance revealed that the immediate effect of ethanol (p = 0.013) and propan-2-ol (p = 0.001) is significantly influenced by the variation of treatments which is mainly explained by the effect of brushing during disinfection. But no significant difference between treatment variations was found in the sustained effect with any of the alcohols. Skin hydration increased significantly by a 1 min hand wash for up to 10 min despite drying hands with a paper towel. A 15 s hand wash reduced the number of bacterial spores significantly from log10 3.84 to log10 1.99 (p = 0.001).

CONCLUSIONS

There is no benefit of a hand wash as part of surgical hand disinfection except that a short hand wash of 15 s can effectively reduce spores. The best time for this short hand wash is at the beginning of work in hospital, but at the latest in the sluice of the operating theatre about 10 min before applying an alcohol-based hand rub to give the skin enough time to dry.

Surgical hand rubbing compared with surgical hand scrubbing: comparison of efficacy and costs

The aim of this study was to compare the efficacy of surgical hand rubbing (SHR) with the efficacy of surgical hand scrubbing (SHS), and to determine the costs of both techniques for surgical hand disinfection. A review of studies reported in the literature that compared the efficacy of SHS and SHR was performed using MEDLINE. The costs of SHR and SHS were estimated based on standard hospital costs. The literature showed that SHR had immediate efficacy that was similar to that of SHS, but SHR had a more lasting effect. SHR reduced costs by 67%. In conclusion, SHR is a cost-effective alternative to SHS.

Emollients in a propanol-based hand rub can significantly decrease irritant contact dermatitis

The objective of this study is to determine the effect of emollients in a propanol-based hand rub on skin dryness and erythema. In this prospective, randomized, controlled, double-blind trial, 35 subjects participated; of them approximately half were atopic (modified Erlanger atopy score > or =8). 2 propanol-based formulations were tested in a repeated open application test, 1 contained a mixture of emollients (0.81%, w/w). 2 aliquots of 0.7 ml of each formulation were applied twice per day over 2 weeks to the cubital fossa of each subject after random assignment of the preparations. Treatment areas were assessed before each application and 3 days postfinal application by visual inspection for erythema and dryness according to a standard scale. The sum score over all assessment time-points served as primary parameter. The mean sum score for erythema and dryness was significantly lower for the hand rub with emollients (0.8 +/- 2.4) in comparison with that for the hand rub without emollients (1.5 +/- 3.5; P = 0.022; Wilcoxon signed rank test). A comparison of the atopic and non-atopic subjects revealed no significant difference for any of the products (P > 0.05; Mann-Whitney U-test). It is concluded that the addition of emollients to a propanol-based hand rub can significantly decrease irritant contact dermatitis under frequent-use conditions.

Multicentre study on hand hygiene facilities and practice in the Mediterranean area: results from the NosoMed Network

Hand hygiene literature is scarce in the southern Mediterranean area. In order to establish a baseline position, a study was performed in four Mediterranean countries. Seventy-seven hospital wards in 22 hospitals were enrolled and information on hand hygiene practice and facilities were collected. The overall compliance rate was very low (27.6%), and was significantly higher where the perceived risk was considered to be high. Intensive care units showed the highest level of compliance. Analysis by country indicated higher compliance in Egypt (52.8%) and Tunisia (32.3%) compared with Algeria (18.6%) and Morocco (16.9%). Facilities for hand hygiene, particularly consumables, were shown to be deficient. Multi-approach programmes combining the production of official local recommendations, education and regular evaluation of hand hygiene practice are much needed to improve the present situation.