Comparative study on the antimicrobial effect of 0.5% chlorhexidine gluconate and 70% isopropyl alcohol on the normal flora of hands

Evaluation of fast-acting bactericidal activity and substantivity of an antiseptic agent, olanexidine gluconate, using an ex vivo skin model

PURPOSE

We assessed the fast-acting bactericidal activity and substantivity of olanexidine gluconate (OLG) to investigate its remaining bactericidal activity on the skin after rinsing and drying by using an ex vivo Yucatan micropig (YMP) skin model.

METHODOLOGY

The fast-acting bactericidal activity was evaluated in pigskin models inoculated with methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, vancomycin-resistant Enterococcus faecalis (VRE), Acinetobacter baumannii, Corynebacterium minutissimum and Cutibacterium acnes. To evaluate substantivity, the YMP skin piece first had 1.5 % OLG, chlorhexidine gluconate (CHG) formulations or 10 % povidone-iodine (PVP-I) applied to it, and was then rinsed with distilled water, incubated for 4, 6, 8 or 12 h and inoculated with the test bacteria (MRSA, S. epidermidis and VRE). The viable bacteria remaining at 1 min of exposure of bacteria were counted to measure the quantity of antiseptic molecules retaining bactericidal activity. To determine the factors contributing to the substantivity, the stratum corneum (SC) of the YMP skin that had had OLG or CHG applied to it was exfoliated using a tape-stripping method and the amount of antiseptic was quantitated.

RESULTS

OLG showed a fast-acting bactericidal activity that was similar to or stronger than that of CHG formulations up to a concentration of 1 % and PVP-I with a short exposure time of 30 s, and substantivity until 12 h after rinsing, whereas the other antiseptics hardly showed any substantivity. There was 2.8 times or more OLG in the SC than CHG.

CONCLUSION

OLG has fast-acting activity and substantivity, which are required properties for an antiseptic, and is useful for preventing infections.

Stratum corneum substantivity: drug development implications

There are at least 15 factors that influence the ability of chemicals to penetrate the skin. Substantivity is yet another factor and allows penetrants to remain on and in skin for many days. As many skin pathologies involve stratum corneum and require multiple dosing of topicals, understanding substantivity mechanisms may provide insight for topical dosing strategies. Substantivity is also of importance in the development of other consumer products that necessitate adherence to skin, including sunscreens, insect repellents, and cosmetics. Furthermore, while stratum corneum adherence may delay percutaneous penetration, reducing the risk of systemic toxicity, excessive substantivity may play a role in the toxic accumulation of harmful penetrants. Continued research in this area may offer insight into dermatotoxicology and dermatopharmacology.

Desiccation and ethanol resistances of multidrug resistant Acinetobacter baumannii embedded in biofilm: The favorable antiseptic efficacy of combination chlorhexidine gluconate and ethanol

BACKGROUND/PURPOSE

Globally, multidrug-resistant Acinetobacter baumannii (MDRAB) has emerged as an important pathogen in nosocomial outbreaks. This study aimed to investigate the correlation between the biofilm formation and survival of MDRABs, and to investigate the antiseptic efficacy of hand sanitizers for the MDRABs, embedded with biofilm (MDRAB-Bs).

METHODS

The MDRABs were selected randomly after pulsed-field gel electrophoresis (PFGE), and their biofilm formation was analyzed. Desiccation and ethanol tolerances were assayed to test the bacterial survival. The antiseptic efficacy of combined chlorhexidine gluconate (CHG) and 70% ethanol agents against MDRAB-Bs were compared with the 70% ethanol cleanser.

RESULTS

Eleven MDRABs, which varied in biofilm formation (MRDAB-B) and planktonic type (MDRAB-P), were tested. In desiccation survival, the mean survival time for the MDRAB-Bs was 49.0 days which was significantly higher than that of their planktonic type (17.3 days) (P < 0.005). The MDRAB-Ps could be eliminated after a 10 min contact with a 30% ethanol agent, however, it took 10 min of 70% ethanol to eliminate the MDRAB-Bs. On the other hand, a 2% CHG in 70% ethanol solution completely eliminated all MDRAB-Bs after 1 min contacted time. The 2% CHG in 70% ethanol agent provided a significantly superior efficacy than the 70% ethanol solution at eliminating the MDRAB-Bs (P < 0.005).

CONCLUSION

MDRAB with biofilm-formation presented significantly higher desiccation and ethanol resistances than their planktonic type. Moreover, the 2% CHG in 70% ethanol agent provided a superior antiseptic efficacy for MDRAB-Bs than that of the 70% ethanol agent.

Quantifying the Effects of Water Temperature, Soap Volume, Lather Time, and Antimicrobial Soap as Variables in the Removal of Escherichia coli ATCC 11229 from Hands

The literature on hand washing, while extensive, often contains conflicting data, and key variables are only superficially studied or not studied at all. Some hand washing recommendations are made without scientific support, and agreement between recommendations is limited. The influence of key variables such as soap volume, lather time, water temperature, and product formulation on hand washing efficacy was investigated in the present study. Baseline conditions were 1 mL of a bland (nonantimicrobial) soap, a 5-s lather time, and 38°C (100°F) water temperature. A nonpathogenic strain of Escherichia coli (ATCC 11229) was the challenge microorganism. Twenty volunteers (10 men and 10 women) participated in the study, and each test condition had 20 replicates. An antimicrobial soap formulation (1% chloroxylenol) was not significantly more effective than the bland soap for removing E. coli under a variety of test conditions. Overall, the mean reduction was 1.94 log CFU (range, 1.83 to 2.10 log CFU) with the antimicrobial soap and 2.22 log CFU (range, 1.91 to 2.54 log CFU) with the bland soap. Overall, lather time significantly influenced efficacy in one scenario, in which a 0.5-log greater reduction was observed after 20 s with bland soap compared with the baseline wash (P = 0.020). Water temperature as high as 38°C (100°F) and as low as 15°C (60°F) did not have a significant effect on the reduction of bacteria during hand washing; however, the energy usage differed between these temperatures. No significant differences were observed in mean log reductions experienced by men and women (both 2.08 log CFU; P = 0.988). A large part of the variability in the data was associated with the behaviors of the volunteers. Understanding what behaviors and human factors most influence hand washing may help researchers find techniques to optimize the effectiveness of hand washing.

Effect of Chlorhexidine Bathing Every Other Day on Prevention of Hospital-Acquired Infections in the Surgical ICU: A Single-Center, Randomized Controlled Trial

OBJECTIVE

To test the hypothesis that compared with daily soap and water bathing, 2% chlorhexidine gluconate bathing every other day for up to 28 days decreases the risk of hospital-acquired catheter-associated urinary tract infection, ventilator-associated pneumonia, incisional surgical site infection, and primary bloodstream infection in surgical ICU patients.

DESIGN

This was a single-center, pragmatic, randomized trial. Patients and clinicians were aware of treatment-group assignment; investigators who determined outcomes were blinded.

SETTING

Twenty-four-bed surgical ICU at a quaternary academic medical center.

PATIENTS

Adults admitted to the surgical ICU from July 2012 to May 2013 with an anticipated surgical ICU stay for 48 hours or more were included.

INTERVENTIONS

Patients were randomized to bathing with 2% chlorhexidine every other day alternating with soap and water every other day (treatment arm) or to bathing with soap and water daily (control arm).

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was a composite outcome of catheter-associated urinary tract infection, ventilator-associated pneumonia, incisional surgical site infection, and primary bloodstream infection. Of 350 patients randomized, 24 were excluded due to prior enrollment in this trial and one withdrew consent. Therefore, 325 were analyzed (164 soap and water versus 161 chlorhexidine). Patients acquired 53 infections. Compared with soap and water bathing, chlorhexidine bathing every other day decreased the risk of acquiring infections (hazard ratio = 0.555; 95% CI, 0.309-0.997; p = 0.049). For patients bathed with soap and water versus chlorhexidine, counts of incident hospital-acquired infections were 14 versus 7 for catheter-associated urinary tract infection, 13 versus 8 for ventilator-associated pneumonia, 6 versus 3 for incisional surgical site infections, and 2 versus 0 for primary bloodstream infection; the effect was consistent across all infections. The absolute risk reduction for acquiring a hospital-acquired infection was 9.0% (95% CI, 1.5-16.4%; p = 0.019). Incidences of adverse skin occurrences were similar (18.9% soap and water vs 18.6% chlorhexidine; p = 0.95).

CONCLUSIONS

Compared with soap and water, chlorhexidine bathing every other day decreased the risk of acquiring infections by 44.5% in surgical ICU patients.

Impact of a Single Plain Finger Ring on the Bacterial Load on the Hands of Healthcare Workers

Objective.

To investigate the impact of a single plain finger ring on the number and types of bacteria on the hands of healthcare workers (HCWs).

Design.

Nonequivalent control groups, posttest only (preexperimental).

Methods.

A total of 121 HCWs wearing 1 plain ring and 113 HCWs wearing no rings had both hands sampled by the “glove juice” technique. Quantitative culture of the samples was performed and microorganisms were identified.

Setting.

Two Norwegian acute care hospitals.

Participants.

A total of 234 HCWs who had physical contact with patients.

Results.

Total bacterial counts did not differ when hands with rings and hands without rings were compared, both according to nonpaired analysis (which compared the ring-bearing hands of ring-wearing HCWs to the hands of HCWs who did not wear rings [P= .661]) and according to paired analysis (which compared the ring-bearing and ring-free hands of ring-wearing HCWs [P= .071]).Staphylococcus aureuswas recovered from 18.6% of the hands sampled, belonging to 26.9% of the HCWs, but neither paired nor nonpaired analysis showed any association with ring wearing. Gram-negative bacteria were recovered from 20.3% of the hands sampled, belonging to 28.6% of the HCWs. Ring-wearing HCWs were significantly more likely to be carriers of Enterobacteriaceae (P= .006), but paired comparison of the ring-bearing and ring-free hands of these HCWs did not show significant differences (P= .180). Carriage of nonfermentative gram-negative rods did not differ between the 2 groups, by either paired or nonpaired analysis.

Conclusions.

Wearing a single plain finger ring did not increase the total bacterial load on the hands, nor was it associated with an increased rate of carriage ofS. aureusor nonfermentative gram-negative rods. However, plain rings were associated with an increased rate of Enterobacteriaceae carriage.

Chlorhexidine is a better antiseptic than povidone iodine and sodium hypochlorite because of its substantive effect

BACKGROUND

The present study compared both the antiseptic efficacy of sodium hypochlorite against that of chlorhexidine gluconate in isopropyl alcohol and the substantive effect of chlorhexidine, povidone iodine, and sodium hypochlorite.

METHODS

This was a 2-step study that included volunteers. In step 1, 4 skin areas were tested for bacteria in colony-forming units (CFU): 2 were controls to determine baseline bacteria or the effect of scrubbing, and 2 were treated with 10% hypochlorite or 2% chlorhexidine in isopropyl alcohol. Every subject was tested 4 times. The second step tested the substantive effect of 10% povidone-iodine and the aforementioned antiseptics.

RESULTS

For the first step, 30 volunteers were studied, resulting in 120 determinations for each control and antiseptic. No differences between chlorhexidine gluconate (median 115 CFU/cm(2)) and sodium hypochlorite (median 115 CFU/cm(2)) were found. Both antiseptics were significantly different from rubbing control (317 CFU/cm(2)) and basal control (606 CFU/cm(2)). Only chlorhexidine showed a substantive effect.

CONCLUSION

We consider that chlorhexidine gluconate in isopropyl alcohol, sodium hypochlorite, and povidone-iodine is equally effective for procedures that do not require a long action. However, chlorhexidine is desirable for procedures such as catheter insertion, skin preparation for surgery, or handwashing prior to surgery.

Comparing hand hygiene measures in a neonatal ICU: a randomized crossover trial

OBJECTIVE

To compare plain soap, alcohol hand rub and iodophors as hand hygiene measures in a neonatal intensive care unit (NICU).

DESIGN

Randomized, crossover, three-armed, controlled trial with blinded outcome measurement.

SETTING

Level III NICU.

PARTICIPANTS

35 NICU nurses.

INTERVENTION

Participants were assigned to plain soap hand washing, alcohol hand rub and povidone-iodine hand scrub by a random cross-over design. Interventions were preceded by 14-day neutral periods. Cultures from hands were taken before and after each hand-hygiene use, prior to 5 patient-care activities.

MAIN OUTCOME MEASURE

The primary outcome was mean post-hygiene colony forming unit count (CFU-C).

RESULTS

There were differences between soap, alcohol and povidone groups vis a vis posthygiene CFUC [median: 60, 8 and 10.5, respectively (P<0.001)], absolute reduction in CFU-C [median: 15, 100 and 40, respectively (P<0.001)], percent reduction in CFUC [median: 33.3, 92 and 87, respectively (P<0.001)] and proportion with low CFU-C [47%, 71% and 72%, respectively (P<0.001)]. Alcohol [Adjusted OR 3.2 (95% CI 1.9, 5.3)], povidone-iodine [AOR 3.1 (95% CI 1.8, 5.3)] and high prehygiene CFU-C (>300) [AOR 0.18 (95% CI 0.1, 0.3)] were independently associated with low CFU-C.

CONCLUSION

After a 2 minute hand wash at entry into NICU, alcohol hand rub and povidone-iodine scrub are superior to plain soap hand wash for subsequent decontamination of hands of nurses working in NICU.

Appropriate time-interval application of alcohol hand gel on reducing influenza-like illness among preschool children: a randomized, controlled trial

BACKGROUND

We studied the efficacy of different time-interval applications of alcohol hand gel as a strategy for the prevention of influenza-like illness (ILI) in preschool-age children.

METHODS

We performed a classroom-based cluster randomization at a kindergarten school in Bangkok, Thailand. A total of 1437 children were placed into 3 test groups, based on the frequency of alcohol hand gel use for hand hygiene: only before lunch (q lunch), every 120 minutes (q 120), and every 60 minutes (q 60). The primary outcome was a change in the school absenteeism rate caused by ILI.

RESULTS

The rates of absenteeism from confirmed ILI (sick days/present days) were 0.026 in the q lunch group, 0.025 in the q 120 group, and 0.017 in the q 60 group. Significant reductions in absenteeism rates were seen when comparing the q 60 group with the q 120 group (rate difference, 0.009; 95% confidence interval [CI], -0.002 to 0.015; P = .008) and comparing the q 60 group with the q lunch group (rate difference, 0.0096; 95% CI, 0.004-0.016; P = .002). No such differences were detected between the q 120 and q lunch groups (rate difference, 0.001; 95% CI, 0.005-0.007; P = .743).

CONCLUSIONS

The compulsory hourly use of alcohol gel as classroom hand disinfection could significantly reduce the rate of absenteeism from ILI in preschool-age children.

Development of an evidence-based protocol for care of pilonidal sinus wounds healing by secondary intent using a modified Reactive Delphi procedure. Part 2: methodology, analysis and results

This is the second part of the article based on the thesis work for a Masters of Science in Wound Healing and Tissue Repair, Cardiff University, to develop an evidence-based protocol for the care of pilonidal sinus wounds (PSWs) healing by secondary intent, using a modified Reactive Delphi process. The sample included surgeons, clinic physicians, nurses and enterostomal therapy nurses experienced in the care of these wounds. Item generation involved an extensive review of the literature to identify key aspects of evidence-based wound care essential to wound healing, infected wounds and pilonidal wounds healing by secondary intent and drawing on clinical experience. The participants responded via an electronic Delphi website, using a 4-point Likert rating scale and a ranking system. Comments were invited. Feedback was provided to the participants at the end of each round, that included comments, consensus scores, content validity index and additional information that provided rationale and references, or minor revision if requested. This project successfully achieved the objectives, which were to identify the areas of care that negatively or positively influences healing of postoperative PSWs and to inform, educate and broaden the considerations regarding these factors for health care professionals.

Development of an evidence-based protocol for care of pilonidal sinus wounds healing by secondary intent using a modified reactive Delphi procedure. Part one: the literature review*

This article is in two parts. The overall aim of this section was to review the literature in relation to pilonidal sinus wounds (PSW) healing by secondary intent for a Master's of Science in Wound Healing and Tissue Repair thesis. The purpose of the literature review was to determine if an evidence-based guideline or consensus document existed for the care of these wounds, and if not, to determine the topics from which to develop items for the first round of a modified reactive Delphi questionnaire. Part two will describe the iterative process, the analysis and the results. The review found no best practice guidelines concerning PSW, and only one clinical pathway. Seventeen areas of interest were identified that may contribute to optimal healing conditions or to delayed healing. These included microbiology of infected PSW, signs and symptoms of localised or deeper (spreading) chronic wound infection, swab for c&s, role of topical antiseptics or antimicrobials, systemic antibiotics, local wound interventions, optimal positioning, wound cleansing, principles of moist wound healing/dressing selection, topical negative pressure (TNP) therapy, peri-wound skin decontamination and depilation, pain control, physical activities, optimal nutrition and patient education.

A meta-analysis of the published literature on the effectiveness of antimicrobial soaps

The goal of this research was to conduct a systematic quantitative analysis of the existing data in the literature in order to determine if there is a difference between antimicrobial and nonantimicrobial soaps and to identify the methodological factors that might affect this difference. Data on hand washing efficacy and experimental conditions (sample size, wash duration, soap quantity, challenge organism, inoculum size, and neutralization method) from published studies were compiled and transferred to a relational database. A total of 25 publications, containing 374 observations, met the study selection criteria. The majority of the studies included fewer than 15 observations with each treatment and included a direct comparison between nonantimicrobial soap and antimicrobial soap. Although differences in efficacy between antimicrobial and nonantimicrobial soap were small (∼0.5-log CFU reduction difference), antimicrobial soap produced consistently statistically significantly greater reductions. This difference was true for any of the antimicrobial compounds investigated where n was >20 (chlorhexidine gluconate, iodophor, triclosan, or povidone). Average log reductions were statistically significantly greater (∼2 log CFU) when either gram-positive or gram-negative transient organisms were deliberately added to hands compared with experiments done with resident hand flora (∼0.5 log CFU). Our findings support the importance of using a high initial inoculum on the hands, well above the detection limit. The inherent variability in hand washing seen in the published literature underscores the importance of using a sufficiently large sample size to detect differences when they occur.

Inactivation of chlorhexidine gluconate on skin by incompatible alcohol hand sanitizing gels

Incompatibility of leave-on products with an antimicrobial residual can negate the efficacy benefits of chlorhexidine gluconate (CHG) persistence. Two marketed alcohol products containing Carbomer were tested using a pigskin substrate model against Staphylococcus aureus. The CHG residual achieved a 4.22 log(10) reduction (standard deviation [SD] = 0.32) in this study, which was dramatically reduced to a 0.54 (SD = 0.50) and 0.46 (SD = 0.56) after subsequent treatment with incompatible alcohol gel products. A marketed alcohol product containing a nonionic thickener maintained the efficacy of the CHG chemical reservoir (log(10) reduction = 4.26, SD = 0.00). Similar findings were demonstrated when alcohol solutions containing the individual thickening agents were tested as simple formulations. An in vivo test using human forearms and Serratia marcescens similarly demonstrated that the activity of a CHG reservoir (log(10) reduction = 3.73, SD = 0.86) was not reduced by a nonionic thickened product (log(10) reduction = 3.98, SD = 0.72) but was significantly reduced by treatment with alcohol products containing anionic thickeners carbomer (log(10) reduction = -0.32, SD = 0.34) or acrylates/C10-30 alkyl acrylate crosspolymer (log(10) reduction = -0.20, SD = 0.32). The use of anionic thickeners or emulsifiers in leave-on products, including alcohol hand sanitizers, may inactivate the persistent antibacterial activity of CHG.

Hand washing rituals in trauma theatre: clean or dirty?

INTRODUCTION

The aim of this study was to investigate the degree of contamination of a surgeon's hand following use of chlorhexidine gluconate or alcohol gel as disinfectants.

MATERIALS AND METHODS

In this prospective, randomised trial, orthopaedic surgeons were allocated to one of two different hand-washing protocols using a randomisation table. The hand-washing protocol dictated that all surgeons should wash for 5 min with chlorhexidine for their first case. Thereafter, the surgeon was randomised to wash for 3 min with either alcohol gel or chlorhexidine. At the end of each procedure, the gloves of each surgeon were carefully removed and the fingertips from each hand were placed on an agar plate. The number of bacterial colonies present after 24 h and 48 h of incubation were recorded for each agar plate by a microbiologist blinded to the washing protocol used.

RESULTS

Overall, 41 procedures and 82 episodes of hand washings were included in the study. Two episodes were discarded due to contamination at the time of glove removal. Four hands (8%) were contaminated in the chlorhexidine group compared to 19 (34%) in the alcohol group. Fisher's exact test confirmed a significantly higher risk of contamination using alcohol gel compared to chlorhexidine (P = 0.002). In addition, the average bacterial colony count was substantially higher in the alcohol group (20 colony forming units) compared to the chlorhexidine group (5 colony forming units). There was no relationship between the duration of surgery and the degree of contamination (P = 1.12).

CONCLUSIONS

Alcohol gel disinfectant is not a suitable alternative to chlorhexidine when hand washing before surgery. This study has identified a higher risk of bacterial contamination of surgeons' hands washed with alcohol. This may lead to higher levels of postoperative infection in the event of glove perforation.

Comparative efficacy of hand hygiene agents in the reduction of bacteria and viruses

Background

Health care-associated infections most commonly result from person-to-person transmission via the hands of health care workers.

Methods

We studied the efficacy of hand hygiene agents (n = 14) following 10-second applications to reduce the level of challenge organisms (Serratia marcescens and MS2 bacteriophage) from the hands of healthy volunteers using the ASTM-E-1174-94 test method.

Results

The highest log₁₀ reductions of S marcescens were achieved with agents containing chlorhexidine gluconate (CHG), triclosan, benzethonium chloride, and the controls, tap water alone and nonantimicrobial soap and water (episode 1 of hand hygiene, 1.60-2.01; episode 10, 1.60-3.63). Handwipes but not alcohol-based handrubs were significantly inferior from these agents after a single episode of hand hygiene, but both groups were significantly inferior after 10 episodes. After a single episode of hand hygiene, alcohol/silver iodide, CHG, triclosan, and benzethonium chloride were similar to the controls in reduction of MS2, but, in general, handwipes and alcohol-based handrubs showed significantly lower efficacy. After 10 episodes, only benzethonium chloride (1.33) performed as well as the controls (1.59-1.89) in the reduction of MS2.

Conclusions

Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.

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

The etiology of nosocomial infections, the frequency of contaminated hands with the different nosocomial pathogens, and the role of health care workers' hands during outbreaks suggest that a hand hygiene preparation should at least have activity against bacteria, yeasts, and coated viruses. The importance of efficacy in choosing the right hand hygiene product is reflected in the new Centers for Disease Control and Prevention guideline on hand hygiene (J. M. Boyce and D. Pittet, Morb. Mortal. Wkly. Rep. 51:1-45, 2002). The best antimicrobial efficacy can be achieved with ethanol (60 to 85%), isopropanol (60 to 80%), and n-propanol (60 to 80%). The activity is broad and immediate. Ethanol at high concentrations (e.g., 95%) is the most effective treatment against naked viruses, whereas n-propanol seems to be more effective against the resident bacterial flora. The combination of alcohols may have a synergistic effect. The antimicrobial efficacy of chlorhexidine (2 to 4%) and triclosan (1 to 2%) is both lower and slower. Additionally, both agents have a risk of bacterial resistance, which is higher for chlorhexidine than triclosan. Their activity is often supported by the mechanical removal of pathogens during hand washing. Taking the antimicrobial efficacy and the mechanical removal together, they are still less effective than the alcohols. Plain soap and water has the lowest efficacy of all. In the new Centers for Disease Control and Prevention guideline, promotion of alcohol-based hand rubs containing various emollients instead of irritating soaps and detergents is one strategy to reduce skin damage, dryness, and irritation. Irritant contact dermatitis is highest with preparations containing 4% chlorhexidine gluconate, less frequent with nonantimicrobial soaps and preparations containing lower concentrations of chlorhexidine gluconate, and lowest with well-formulated alcohol-based hand rubs containing emollients and other skin conditioners. Too few published data from comparative trials are available to reliably rank triclosan. Personnel should be reminded that it is neither necessary nor recommended to routinely wash hands after each application of an alcohol-based hand rub. Long-lasting improvement of compliance with hand hygiene protocols can be successful if an effective and accessible alcohol-based hand rub with a proven dermal tolerance and an excellent user acceptability is supplied, accompanied by education of health care workers and promotion of the use of the product.

The effects of test variables on the efficacy of hand hygiene agents

BACKGROUND

Hand hygiene is essential to interrupting disease transmission in health care facilities. Multiple hand hygiene agents are currently available for use in the health care setting. To evaluate the utility of these agents, both the user acceptability and the efficacy need to be evaluated. Different hand hygiene test methodologies have been used to measure the efficacy of these agents, but efficacy results vary depending on variations to key parameters in these methodologies. The purpose of this study was to evaluate the effect of test variables on the efficacy of hand hygiene agents.

METHODS

Both a comprehensive literature review and original hand hygiene efficacy studies were undertaken. The literature review was conducted using a Medline search, and hand hygiene efficacy studies were conducted under the American Society for Testing and Materials (ASTM). E 1174 Standard Test Method for Evaluation of the Effectiveness of Health Care Personnel Handwash Formulation.

RESULTS

The literature review and our original data showed that the following variables affected the hand hygiene efficacy measurements: hand jewelry, experimental contamination versus normal flora, method of application of test organism, hand hygiene agent, concentration of active ingredient, volume of hand hygiene agent, duration of application of hand hygiene agent, method of application of hand hygiene agent, and study method (human challenge trial versus in vitro suspension test).

CONCLUSIONS

Although many methodological variables affect efficacy results, infection control professionals in their analysis of product information should always assess the results in light of the following key variables: concentration and type of active ingredient, duration of exposure to hand hygiene agent, volume of hand hygiene agent applied, test organism, and study method (ie, human challenge vs. in vitro suspension test).

Guideline for Hand Hygiene in Health-Care Settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HIPAC/SHEA/APIC/IDSA Hand Hygiene Task Force

The Guideline for Hand Hygiene in Health-Care Settings provides health-care workers (HCWs) with a review of data regarding handwashing and hand antisepsis in health-care settings. In addition, it provides specific recommendations to promote improved hand-hygiene practices and reduce transmission of pathogenic microorganisms to patients and personnel in health-care settings. This report reviews studies published since the 1985 CDC guideline (Garner JS, Favero MS. CDC guideline for handwashing and hospital environmental control, 1985. Infect Control 1986;7:231-43) and the 1995 APIC guideline (Larson EL, APIC Guidelines Committee. APIC guideline for handwashing and hand antisepsis in health care settings. Am J Infect Control 1995;23:251-69) were issued and provides an in-depth review of hand-hygiene practices of HCWs, levels of adherence of personnel to recommended handwashing practices, and factors adversely affecting adherence. New studies of the in vivo efficacy of alcohol-based hand rubs and the low incidence of dermatitis associated with their use are reviewed. Recent studies demonstrating the value of multidisciplinary hand-hygiene promotion programs and the potential role of alcohol-based hand rubs in improving hand-hygiene practices are summarized. Recommendations concerning related issues (e.g., the use of surgical hand antiseptics, hand lotions or creams, and wearing of artificial fingernails) are also included.

Guideline for Hand Hygiene in Health-Care Settings: recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force

The Guideline for Hand Hygiene in Health-Care Settings provides health-care workers (HCWs) with a review of data regarding handwashing and hand antisepsis in health-care settings. In addition, it provides specific recommendations to promote improved hand-hygiene practices and reduce transmission of pathogenic microorganisms to patients and personnel in health-care settings. This report reviews studies published since the 1985 CDC guideline (Garner JS, Favero MS. CDC guideline for handwashing and hospital environmental control, 1985. Infect Control 1986;7:231-43) and the 1995 APIC guideline (Larson EL, APIC Guidelines Committee. APIC guideline for handwashing and hand antisepsis in health care settings. Am J Infect Control 1995;23:251-69) were issued and provides an in-depth review of hand-hygiene practices of HCWs, levels of adherence of personnel to recommended handwashing practices, and factors adversely affecting adherence. New studies of the in vivo efficacy of alcohol-based hand rubs and the low incidence of dermatitis associated with their use are reviewed. Recent studies demonstrating the value of multidisciplinary hand-hygiene promotion programs and the potential role of alcohol-based hand rubs in improving hand-hygiene practices are summarized. Recommendations concerning related issues (e.g., the use of surgical hand antiseptics, hand lotions or creams, and wearing of artificial fingernails) are also included.

Investigations into the efficacy of different procedures for surgical hand disinfection between consecutive operations

In order to examine whether thorough surgical hand disinfection (handwashing plus hand disinfection) between consecutive operations is necessary, tests were carried out simulating normal clinical conditions. The tests were performed according to the guidelines for the evaluation of disinfection procedures of the German Society for Hygiene and Microbiology. Surgical hand disinfection was as follows: handwashing with soap without antimicrobial additives and subsequent 5-min disinfection with 60% n-propanol. This was followed by simulated operations of 30 or 120 min duration with a 30-min break between operations, during which half of the test group kept on the surgical gloves, while the other half removed them. The second surgical hand disinfection was done without prior handwashing by 50% of the test group. The disinfection time was reduced from 5 to 1 min by 50% of the test group. The results were evaluated by means of explorative data analysis and inductive statistical methods. Removing the surgical gloves during the interoperative break did not result in significantly higher numbers of colony forming units (cfu) compared with retaining the gloves. This was also the case after a subsequent handwashing. At the second surgical hand disinfection, after a simulated operation of 60 min duration (including break), there was no significant difference in the numbers of cfus between the test group who had washed their hands and those who had not. Reducing the disinfection time from 5 min to 1 min was not associated with a significant increase in the number of cfus. However, after a simulated operating time of 150 min (including the break), the second surgical hand disinfection with handwashing resulted in a significantly lower number of microorganisms than disinfection alone. In half the tests, the numbers of cfu were significantly lower when the test group disinfected their hands for 5 min rather than 1 min.

Hygienic hand disinfection: a comparative study with chlorhexidine detergents and soap

The efficacy of two chlorhexidine hand-wash detergents and liquid soap was compared in a laboratory trial using artificial contamination of fingers with Micrococcus and Serratia. Agents were assessed for both a rapid and sustained effect after a single contact, and for a cumulative persistent effect after multiple contact over four days. Disinfectant activities were compared by statistical analysis of log reduction factors and log count time gradients (decimal reduction times). The latter analysis attempted to accommodate significant subject variation in response to both agent and organism. All handwashing methods significantly reduced contamination levels. Both chlorhexidine formulations were significantly better than soap in their activity against Micrococcus, but were not more effective than soap in removing contamination with Serratia. Both chlorhexidine preparations showed significant skin persistence and were generally acceptable to subjects after prolonged use. Some effect of the formulation of the hand-wash on chlorhexidine activity was demonstrated.

Comparative evaluation of the immediate and sustained antibacterial action of two regimens, based on triclosan- and chlorhexidine-containing handwash preparations, on volunteers

The degerming effect of a 3 min handwash with 2% triclosan, or 4% chlorhexidine, in detergent and enhanced efficacy of either antiseptic in isopropyl alcohol, was evaluated in volunteers. Handwashing with either antiseptic preparation reduced the normal flora by a factor of 10; alcohol rubbing by approximately a factor of 1000. Both regimens eliminated Micrococcus roseus, artificially inoculated before every procedure. The sustained action of the same detergent preparations was further studied in gloved and ungloved hands by the Vinson's 'finger imprint test'. In the gloved hand both antiseptics inhibited Staphylococcus epidermidis for 4 h. In the ungloved hand however, triclosan remained active longer than chlorhexidine. Whilst the activity of chlorhexidine was short-lived against a clinical isolate of S. aureus, particularly in the ungloved hand, the sustained effect of triclosan against the same strain persisted for 4 h on either hand.

Hygienic hand disinfection

The purpose of hygienic hand disinfection is to render hands safe after contact with pathogens. Comparing effects of disinfection procedures on infection ratios is too difficult for routine purposes but the degerming efficacy may be determined in laboratory tests with volunteers. In the Vienna test model the efficacy of a specific procedure being tested is compared to that of a standard disinfection (rubbing into hands 3 ml of isopropanol 60% v/v, 30 seconds, twice) tested in parallel with the same volunteers. This ensures standardization, thus comparability of results between laboratories, and provides the investigator with a yardstick for efficacy. The model includes artificial contamination, assessment of the release of test bacteria (E. Coli ATCC 11229) before and after disinfection by the finger tip method, and addition of neutralizers to sampling fluids. Alcohols in appropriate concentrations are highly effective (log reductions: greater than 4.0) whereas procedures employing disinfectant detergents act like soap (log reductions: less than or equal to 3.2) and may cause dissemination of pathogens.

Comparative antimicrobial activity, in vitro and in vivo, of soft N-chloramine systems and chlorhexidine

Antimicrobial activity of the following four new N-chloramine compounds was evaluated: two chlorinated simple amino acids, a chlorinated half-ester of succinic acid, and a chlorinated half-ester of glutaric acid. For comparison, the known bactericidal agents 3-chloro-4,4-dimethyl-2-oxazolidinone and chlorhexidine were evaluated by the same procedure. The contact germicidal efficiency screen was used to examine the in vitro bactericidal activity of all six compounds in the absence and presence of 5% horse serum or 5% Triton X-100. The four new compounds were found to have greater germicidal activity than the other compounds tested and to exhibit low toxicity and skin irritation values. The in vivo bactericidal activity was evaluated in two studies. In the occlusion test, three of the four new compounds plus chlorhexidine diacetate were tested. The N-chloramines were significantly superior to chlorhexidine in preventing the expansion of the normal flora under occlusion. In the scrub test, a gloved-hand wash method was used to compare the antimicrobial effect of a 1% solution of the chlorinated half-ester of succinic acid in triacetin with that of a commercial germicidal hand wash containing 4% chlorhexidine gluconate. The two preparations exhibited essentially the same hand-degerming activity.

Antimicrobial activity of chlorhexidine gluconate against natural and artificial contamination during simulation of in-use conditions

Commercial bottles containing chlorhexidine gluconate (antimicrobial skin cleanser), whether exposed to room atmosphere or experimentally inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas cepacia, and Proteus mirabilis, did not exhibit microbial growth.