Alcohol-based hand disinfection: a more robust hand-hygiene method in an intensive care unit

This study involved observation of hand-hygiene behaviour and evaluation of the effect of alcohol-based hand disinfection and handwashing with plain liquid soap on microbial flora. The study was performed in a combined medical and surgical intensive care unit. We demonstrated a crude compliance of hand hygiene of 50.4%, which was only performed adequately in 20.8% of cases. Of this group, handwashing and hand-disinfection procedures were performed properly 34.0% and 71.6% of the time, respectively. Hand samples for bacteriological examinations with the glove juice method demonstrated that whilst handwashing was sensitive to the way in which hand hygiene was performed, alcohol-based hand disinfection was less sensitive to such performance. Our study demonstrated that alcohol-based hand disinfection is a robust hand-hygiene method with many advantages in a practical setting. It is very feasible for use in hospital wards.     

Evaluation of an alcohol-based surgical hand disinfectant containing a synergistic combination of farnesol and benzethonium chloride for immediate and persistent activity against resident hand flora of volunteers and with a novel in vitro pig skin model.

OBJECTIVE: To evaluate the immediate, persistent and sustained in vivo activity of an alcohol-based surgical hand disinfectant, consisting of a zinc gel and a preservative system containing a synergistic combination of farnesol and benzethonium chloride (ZBF disinfectant), and to develop a pig skin model for in vitro evaluation of the immediate and persistent efficacy of alcohol-based surgical hand disinfectants against resident hand flora. DESIGN: The in vivo immediate, persistent, and sustained activity of ZBF disinfectant was evaluated using human volunteers and the "glove-juice" method described in the US Food and Drug Administration's Tentative Final Monograph (FDA-TFM) for Healthcare Antiseptic Products. A novel in vitro pig skin model was developed to compare the immediate and persistent activity of alcohol-based surgical hand disinfectants against resident flora using Staphylococcus epidermidis as the test organism. Four alcohol-based surgical hand disinfectants were evaluated using this model. RESULTS: The results for the ZBF disinfectant exceed the FDA-TFM criteria for immediate, persistent, and sustained activity required for surgical hand disinfectants. The reduction factors for the 4 hand disinfectants obtained using the pig skin model show good agreement with the log(10) reductions in concentrations of hand flora obtained using human volunteers to test for immediate and persistent activity. CONCLUSION: The ZBF disinfectant we evaluated met the FDA-TFM criteria for surgical hand disinfectants. The immediate and persistent efficacy of the surgical hand disinfectants evaluated with the novel pig skin model described in this study shows good agreement with the results obtained in vivo.     

Efficacy of glove combinations in reducing cell culture infection after glove puncture with needles contaminated with human immunodeficiency virus type 1.

OBJECTIVE: To study the effect of various latex and treated glove combinations in reducing the frequency of human immunodeficiency virus (HIV) infection of tissue culture cells after puncture by surgical needles contaminated with infectious human immunodeficiency virus type 1 (HIV-1). DESIGN: One, two, or three layers of sterile latex glove material, or two latex layers with intermediate cotton or Kevlar (with or without the virucidal compound nonoxynol-9) were used to cover 24-well cell culture dishes containing MT2 cells in cell culture medium. Surgical needles wet with cell culture medium containing HIV-1 (HTLV IIIA strain) were passed through the glove materials into the culture medium in the wells of the culture dishes. The culture medium in each well was then assayed biweekly for HIV-1 p24 antigen as a test for infection of cells in the well. RESULTS: The rate of HIV-1 infection of cell cultures after glove puncture was greater than 90% with a single latex surgical glove barrier, 23% to 60% with double or triple layers of latex gloves, less than 8% with an intermediate cotton glove impregnated with 4% nonoxynol-9, 6% with an intermediate Kevlar glove, and 0% with an intermediate Kevlar glove impregnated with nonoxynol-9. CONCLUSIONS: An intermediate glove of Kevlar or of Kevlar or cotton impregnated with virucidal compound nonoxynol-9 between standard latex gloves may improve surgical glove safety, compared with latex gloves alone with respect to needlestick transmission of HIV-1. The experimental model used may permit rapid investigation of other glove systems as barriers to the transfer of infectious agents through gloves by needlestick.     

A novel method of assessing the effectiveness of protective gloves--results from a pilot study

We have devised a novel method for evaluating the effectiveness of protective gloves and have undertaken a small study to assess this approach. Three types of glove were tested in a standardised simulation test with a permethrin-based pesticide. Prewashed cotton gloves were used to collect the samples. One was worn over the protective glove on one hand to measure the potential deposition of pesticide on the hands had the gloves not been worn. A second was placed under the protective glove on the opposite hand to measure the actual deposition of permethrin on the hands when the gloves were worn. This regime was reversed half way through each test in an attempt to prevent bias. Measurable inner glove contamination occurred on 25 out of 30 occasions. Geometric mean protection factors were calculated from the ratio of outer and inner sampling glove contamination, with average protection factors of 470, 200 and 96 being obtained for the two nitrile and PVC gloves, respectively. The PVC gloves were the least effective in preventing inner glove contamination, probably because the glove was thick and fairly inflexible, causing more pesticide to enter the glove around the cuff. Although the tasks were standardised, variability occurred due to worker behaviour and equipment failure. The spray pump failed on five occasions, resulting in higher levels of inner glove contamination and a geometric mean protection factor of 32. On the occasions when the pump worked correctly, the level of protection provided by the gloves rose dramatically with mean protection factors of 220 and 450 being obtained for workers categorised as "messy" and "tidy", respectively.     

Glove use and the relative risk of acute hand injury: a case-crossover study

The purpose of this study was to investigate the relationship between glove use and acute traumatic occupational hand injury. We used a case-crossover, within-subject study design to control for differences between individuals such as occupation, injury history, age, gender, risk-taking behavior, manual dexterity, and muscle strength. A total of 1166 hand-injured workers were interviewed regarding the use of gloves at the time of the injury. The self-reported average duration of glove use in the previous work month was the measure of expected exposure to wearing gloves. Nineteen percent of subjects reported wearing gloves at the time of the injury. The expected exposure to glove use in the past work month was 27.9%. Glove use was associated with a lower risk of lacerations and punctures but not crush, fractures, avulsions, amputations, dislocations; the risk of the former two injury types was estimated to be 60-70% lower while wearing gloves. Glove use is only one component of a comprehensive hand injury prevention approach that might include the identification and elimination of sharp hazards, engineering controls, safety warnings, training in high-risk situation awareness, and proper selection and timing of glove use.     

Whole glove permeation of cyclohexanol through disposable nitrile gloves on a dextrous robot hand and comparison with the modified closed-loop ASTM F739 method 1. No fist clenching

The aim was to develop a whole glove permeation method for cyclohexanol to generate permeation parameter data for a non-moving dextrous robot hand (normalized breakthrough time t_b, standardized breakthrough time t_s, steady state permeation rate P_s, and diffusion coefficient D). Four types of disposable powderless, unsupported, and unlined nitrile gloves from the same producer were investigated: Safeskin Blue and Kimtech Science Blue, Purple, and Sterling. The whole glove method developed involved a peristaltic pump for water circulation through chemically resistant Viton tubing to continually wash the inner surface of the test glove via holes in the tubing, a dextrous robot hand operated by a microprocessor, a chemically protective nitrile glove to protect the robot hand, an incubator to maintain 35°C temperature, and a hot plate to maintain 35°C at the sampling point of the circulating water. Aliquots of 1.0 mL were sampled at regular time intervals for the first 60 min followed by removal of 0.5 mL aliquots every hour to 8 hr. Quantification was by the internal standard method after gas chromatography-selective ion electron impact mass spectrometry using a non-polar capillary column. The individual glove values of t_b and t_s differed for the ASTM closed loop method except for Safeskin Blue, but did not for the whole glove method. Most of the kinetic parameters agreed within an order of magnitude for the two techniques. The order of most protective to least protective glove was Blue and Safeskin, then Purple followed by Sterling for the whole gloves. The analogous order for the modified F739 ASTM closed loop method was: Safeskin, Blue, Purple, and Sterling, almost the same as for the whole glove. The Sterling glove was “not recommended” from the modified ASTM data, and was “poor” from the whole glove data.     

白色假丝酵母菌对常用消毒剂抗力的观察

目的了解常用3种消毒剂聚维酮碘、手消毒剂、氯氧三嗪(三氯异氰尿酸)泡腾片对医院感染白色假丝酵母菌与标准菌株的杀灭效果是否存在差异,临床株对这3种消毒剂是否产生抗力。方法用肉汤稀释法进行最低抑菌浓度(MIC)及最小杀菌浓度(MBC)测定,采用悬液定量杀菌试验了解消毒剂对细菌的杀灭率。结果聚维酮碘对8株临床分离的白色假丝酵母菌和标准株的MIC、MBC有所不同,而手消毒剂、氯氧三嗪泡腾片则差异无统计学意义;100mg/L聚维酮碘、1/16手消毒剂、250mg/L氯氧三嗪泡腾片对标准株和8株临床株作用10min的杀灭率均达100%。结论 8株临床分离的白色假丝酵母菌对聚维酮碘的抗力有所不同,但未检测到对手消毒剂、氯氧三嗪泡腾片产生抗力的临床株;在临床应用中,适当的延长消毒剂的作用时间可以达到杀灭白色假丝酵母菌的效果。     

Influence of rings on the efficacy of hand sanitization and residual bacterial contamination.

BACKGROUND: Previous studies, conducted before widespread use of scrubless, alcohol-based hand sanitizers, demonstrated increased residual bacterial counts after hand hygiene on hands with jewelry. OBJECTIVE: To compare the impact of finger rings on the effectiveness of scrubless and water-aided alcohol-based hand sanitization methods with that of povidone-iodine scrub. DESIGN: Randomized, controlled study.Setting. University hospital.Participants. Sixty volunteer subjects from a pool of perioperative staff and medical students. INTERVENTION: After recruitment, participants wore a ring on one hand and no ring on the other hand. They were randomly assigned to perform hand hygiene with a povidone-iodine scrub, an alcohol wash, or a waterless alcohol-chlorhexidine lotion (n=20 subjects per method). After subjects completed hand hygiene, gloves were placed on their hands by means of sterile methods, and a "glove juice" technique was used to obtain samples for culture. The number of colony-forming units in each culture was counted, and the data were compared. RESULTS: There was no significant difference in the number of bacteria between hands with and hands without rings for the groups that used alcohol wash or alcohol-chlorhexidine lotion. However, for the povidone-iodine group, the number of bacteria on hands with rings was greater than the number on hands without rings (P<.05). The hands of participants who used waterless alcohol-chlorhexidine had the lowest bacterial count, regardless of the presence of rings (P<.01). CONCLUSIONS: The presence of rings does not negatively impact the effectiveness of alcohol-based hand sanitizers. Use of waterless alcohol-chlorhexidine lotion resulted in the lowest bacterial count.     

Whole glove permeation of cyclohexanol through disposable nitrile gloves on a dextrous robot hand: Fist clenching vs. non-clenching

The differences in permeation parameters when a gloved dextrous robot hand clenched and did not were investigated with the dynamic permeation system described in the companion paper. Increased permeation through the gloves of the present study for cyclohexanol when the gloved hand clenched depended on glove thickness and porosity for cyclohexanol permeation. The Sterling glove, the thinnest and most porous, was the least protective. Hand clenching promoted more permeation for the Sterling glove in terms of breakthrough times, steady state permeation rate, and diffusion coefficient. The Safeskin glove showed increased permeation only for the steady state permeation rate but not breakthrough times or diffusion coefficient. The Blue and Purple gloves showed no differences when the hand was clenching or not. The correlational analysis supported differences between the clenching and non-clenching situations, and the risk assessment considered the worst and best scenarios relative to one and two hydrated hands that were and were not protected by specific gloves.     

A method for reducing adaptor misalignment when testing gloves using ISO 10819

OBJECTIVES: International standard ISO 10819 was established in order to quantify the vibration attenuation characteristics of anti-vibration gloves. One problem that exists with the standard is possible misalignment of the palm adaptor that is placed underneath the test glove. If the adaptor becomes misaligned, the measured glove transmissibility will be lower than the actual value. A tri-axial accelerometer was installed in the adaptor and was used as the basis for providing visual feedback of the adaptor alignment to the test subjects. The objective of this study was to test the hypothesis that adaptor misalignment could be reduced by providing feedback to the test subjects. METHODS: Eight male volunteers (mean age 24.8 yr) were used in the study. Each subject performed two sets of tests: the standard ISO 10819 glove test and the modified version. Three different anti-vibration gloves were tested. Glove transmissibility and adaptor misalignment were calculated for each glove. A three-way analysis of variance was used to analyze the results. RESULTS: A comparison of the two testing methods showed that the modified glove testing method did reduce misalignment significantly, which, in turn, resulted in an increase in the measured glove transmissibility. CONCLUSIONS: The proposed method greatly improved the standard deviation of transmissibility and made the test results more consistent.     

Surgical hand disinfection: comparison of 4% chlorhexidine detergent solution and 2% triclosan detergent solution

The effect of 4% chlorhexidine detergent and 2% triclosan detergent on the resident flora of the hands was compared on 20 healthy volunteers. The initial and prolonged effects of the agents were assessed by a modification of the Peterson glove rinse test after multiple hand washes. Chlorhexidine detergent was significantly more effective than triclosan detergent (p less than 0.001) which in turn was more effective than non-medicated soap (p less than 0.001) for both initial and prolonged effect. Chlorhexidine, but not triclosan, showed a significantly greater prolonged effect than initial effect (p less than 0.01). Five volunteers (25%) experienced skin irritation with triclosan; no side effects were experienced with chlorhexidine.     

An in-use evaluation of an alcohol-based pre-surgical hand disinfectant.

OBJECTIVE: To determine whether alcohol hand disinfection is an effective alternative to traditional agents for the pre-surgical scrub. DESIGN: A prospective clinical trial of a 70% isopropanol pre-surgical hand disinfectant. SETTING: The operating room suites at two hospital sites in British Columbia. METHODS: Cases were selected to evaluate both short and longer procedures. The hand disinfectant was compared to agents in current use as surgical scrubs (4% chlorhexidine and 7.5% povidone-iodine). Surgical technique and glove use were not modified. Pre- and postoperative fingertip impression and "glove-juice" cultures were used to determine microbial burden, and hands were evaluated for skin integrity. RESULTS: There was no statistical difference between the microbial hand counts following use of the alcohol-based product or the current agents, for cases less than 2 hours' duration. Comparison of longer surgical cases revealed significantly better pre- and postoperative culture results with the alcohol hand rinse, but analysis of matched pairs showed no significant difference in microbial counts. The alcohol hand rinse was equivalent to the operative scrub in terms of skin integrity and user acceptability. CONCLUSION: An alcohol hand rinse was equivalently effective in reducing microbial hand counts as the traditional pre-surgical scrub, both immediately after hand disinfection and at the end of the surgical procedure.     

Standardization of needlestick injury and evaluation of a novel virus-inhibiting protective glove

Rubber surgical gloves worn as a barrier to prevent contamination from body fluids offer relative protection against contamination through direct percutaneous injuries involving needles, scalpel blades or bone fragments. To determine the main experimental parameters influencing the volume of blood transmitted by a hollow-bore needle (worst case scenario) during an accidental puncture, we designed an automatic puncture apparatus. Herpes simplex type 1 virus (HSV1), a model for enveloped viruses, was used as a 'marker' in an in-vitro gelatine model. Of the experimental parameters studied, the most critical influences were found to be needle diameter and puncture depth, whereas puncture speed, puncture angle and glove-stretching feature appeared to be less influential. A single glove reduced the volume of blood transferred by 52% compared with no glove, but double gloving offered no additional protection against hollow-bore needle punctures. Using 'standardized' puncture conditions, the virus-inhibiting surgical glove G-VIR elicited an 81% reduction in the amount of HSV1 transmitted as compared with single or double latex glove systems.     

Natural rubber latex: glove use, sensitization, and airborne and latent dust concentrations at a Denver hospital

Exposure to natural rubber latex may cause immediate hypersensitivity reactions. Published latex sensitization prevalence rates range from 2.9% to 22% among health care workers, and from 0.12% to about 20% of occupationally unexposed populations. In this study, self-administered questionnaires addressed job and personal characteristics, glove use, and symptoms in two groups of hospital workers: those who regularly used latex gloves and those who did not. Serum was tested for latex-specific immunoglobulin E. Air, surface, and air-filter dust samples for natural rubber latex were collected. The prevalence of latex sensitization was 6.3% in the non-users and 6.1% in the latex glove users (P = 0.9); 81.3% of sensitized workers were atopic compared with 59.5% of non-sensitized workers (P < 0.05). Reporting of work-related hand dermatitis was more common in the latex glove users (23.4%) than in the non-users (4.9%), as were rhino-conjunctivitis (16.3% and 7.9%, respectively, [P < 0.01]), and hand urticaria (9.9% and 2.1%, respectively, [P < 0.01]). There was no significant difference in work-related symptoms between the sensitized and non-sensitized workers. Environmental concentrations of latex were higher in the work areas of the non-sensitized workers, but higher in the clinical than in the non-clinical areas. Occupational latex glove use was not a risk factor for sensitization.     

Hand disinfection according to the European Standard EN 1500 (hygienic handrub): a study with gram-negative and gram-positive test organisms.

It was the aim of this study to compare the efficacy of alcohol-based hand disinfectants according to European Standard EN 1500 (hygienic handrub), using the routine test organism Escherichia coli and, additionally, Micrococcus luteus as a surrogate for Gram-positive pathogens. One ethanol-based hand disinfectant (product A) and one propanol-based hand disinfectant (product B) were used in all experiments. Product B (propanol-based) was significantly more effective against both test organisms than product A (ethanol-based) in quantitative suspension tests but not in tests simulating practical conditions. In the experiments according to EN 1500 germ reduction rates obtained with the ethanol-containing formulation A were identical for E. coli and M. luteus. Product B was slightly, but not significantly more effective against M. luteus. To conclude, using E. coli as the test organism for evaluating the antibacterial efficacy of alcoholic hand disinfectants under practical conditions even appears to be sufficient to permit the drawing of conclusions for Gram-positive pathogens. However, more alcohol-based hand disinfectants should be tested in further studies to verify the results obtained.     

Determination of the attenuation properties of laboratory gloves exposed to an ultraviolet transilluminator

The transmission of ultraviolet radiation (UVR) from an ultraviolet transilluminator through three types of laboratory gloves (latex, nitrile, vinyl) was determined using two independent methods. First, transmittance was measured with a radiometer equipped with UVA and actinic UV detectors. Second, a spectrophotometer was used to determine the UVR transmittance vs. wavelength (250-440 nm); this data was then used to compute the effective attenuation of the glove material. The average UVA percent transmittance using the radiometer method with an unstretched glove was 73.4%, 0.18%, and 1.10% for vinyl, nitrile, and latex, respectively. The average actinic percent transmittance for an unstretched glove was 13.3%, 0.015%, and 0.024% for vinyl, nitrile, and latex, respectively. Slight increases in UVR transmittance resulted from stretching the gloves by 30% or wetting them with saline. Six hours of UVR exposure decreased transmittance of vinyl gloves and increased transmittance by latex gloves. Results from the spectrophotometer method and radiometer methods of determining UVR transmittance agreed that vinyl gloves had the highest transmittance; however, the spectrophotometer method greatly overestimated UV glove attenuation due to the effect of light scattering by the glove material. The study suggests that in some circumstances, vinyl gloves will provide inadequate protection against workplace ultraviolet radiation.     

Assessment of new chemical disinfectants for HBV virucidal activity in a cell culture model

Several new chemical disinfectants were processed for Hepatitis B virus (HBV) virucidal activity in a cell culture model. A pooled HBV infected human plasma with 10(10.4) HBV DNA copies/mL was treated with the tested disinfectant. It was then subjected, for three days at several dilutions, to cell culture using the human hepatoma cell line, HepG2, with 4% polyethyleneglycol and 3 mM sodium butyrate. Thirty-seven assays were performed on 12 products, with up to 3 concentrations and 3 time exposures for each product tested. The mean viral titre without disinfectant was 10(5.18) infectious units per mL. Our results showed that products all four hand rubs examined, two of the three surface disinfectants and two of the three instrument disinfectants were highly active whatever concentrations and time exposures, reducing viral times by factors of 10(3)-10(4). However, other products such as one of the surface disinfectants was only active at concentrations above 0.5% for 15 min. Similarly the skin disinfectant, one of the instrument disinfectants and the hand wash agent (diluted to 50%) were less or not active (of <10(3) fold reduction). This is the first study using a cell culture model to assess virucidal activity against HBV of new disinfectants. It showed that most 9/12 products were active by either HBs antigen alteration (8/9) or probable envelope disruption (1/9). Further studies are in progress using this model to assess the activity of other chemical disinfectants such as peracetic acid against HBV.     

Evaluating the effectiveness of gloves in reducing the hazards of hand- transmitted vibration

OBJECTIVES: A method of evaluating the effectiveness of gloves in reducing the hazards of hand-transmitted vibration is proposed. METHOD: The glove isolation effectiveness was calculated from: (a) the measured transmissibility of a glove, (b) the vibration spectrum on the handle of a specific tool (or class of tools), and (c) the frequency weighting indicating the degree to which different frequencies of vibration cause injury. With previously reported tool vibration spectra and glove transmissibilities (from 10-1000 Hz), the method was used to test 10 gloves with 20 different powered tools. RESULTS: The frequency weighting for hand-transmitted vibration advocated in British standard 6842 (1987) and international standard 5349 (1986) greatly influences the apparent isolation effectiveness of gloves. With the frequency weighting, the gloves had little effect on the transmission of vibration to the hand from most of the tools. Only for two or three tools (those dominated by high frequency vibration) did any glove provide useful attenuation. Without the frequency weighting, some gloves showed useful attenuation of the vibration on most powered tools. CONCLUSIONS: In view of the uncertain effect of the vibration frequency in the causation of disorders from hand-transmitted vibration, it is provisionally suggested that the wearing of a glove by the user of a particular vibratory tool could be encouraged if the glove reduces the transmission of vibration when it is evaluated without the frequency weighting and does not increase the vibration when it is evaluated with the frequency weighting. A current international standard for the measurement and evaluation of the vibration transmitted by gloves can classify a glove as an antivibration glove when it provides no useful attenuation of vibration, whereas a glove providing useful attenuation of vibration on a specific tool can fail the test.       

Assessing the performance of anti-vibration gloves—A possible alternative to ISO 10819, 1996

Special gloves (commonly referred to as anti-vibration gloves) have been offered for many years as personal protection against hand-arm vibration generated, for example, by powered hand tools. An internationally agreed means of quantifying the vibration-reducing performance of such gloves was not available until the publication of International Standard ISO 10819, 1996. The evaluation of the Standard reported here has led to the conclusion that the test could be improved to give more information to the potential glove user about how the glove might perform. Investigations of the main factors which can influence the results of glove transmissibility tests have formed the basis for a proposal to develop the Standard. The proposed alternative test measures the performance of a glove in octave bands and the resultant data can be used to estimate the potential that the glove has to protect against any given vibration source. Examples of the application of the proposed alternative test for selection of anti-vibration gloves matched to particular vibration sources (powered hand tools) are given. The advantages and disadvantages of the two test methods are discussed. The evaluation of the Standard and proposals for its development are under discussion with members of the committee which developed ISO 10819, 1996.     

Cross Contamination: Are Hospital Gloves Reservoirs for Nosocomial Infections?

Use of disposable nonsterile gloves in the hospital setting is second only to proper hand washing in reducing contamination during patient contact. Because proper handwashing is not consistently practiced, added emphasis on glove use is warranted. There is a growing body of evidence that glove boxes and dispensers available to healthcare workers are contaminated by daily exposure to environmental organisms. This finding, in conjunction with new and emerging antibiotic-resistant bacteria, poses a threat to patients and healthcare workers alike. A newly designed glove dispenser may reduce contamination of disposable gloves. The authors investigated contamination of nonsterile examination gloves in an Emergency Department setting according to the type of dispenser used to access gloves. A statistically significant difference existed between the number of bacterial colonies and the type of dispenser: the downward-facing glove dispenser had a lower number of bacteria on the gloves. There was no statistically significant difference in the number of gloves contaminated between the two types of glove dispensers. The study demonstrated that contamination of disposable gloves existed. Additional research using a larger sample size would validate a difference in the contamination of disposable gloves using outward or downward glove dispensers.