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By Thomas L. Kovach
Historically, phenolic antibacterials such as triclosan and PCMX have been used as active ingredients in handwashing and antimicrobial products for healthcare workers (HCWs). They have been formulated with surfactants to affect micellar solubilization. Due to their sparse water solubility and solubilization inside of surfactant micelles, the biocides may not be in a bioavailable state as a percent in formulation.
Published research indicates that for structurally non-specific biocides, the activity of triclosan depends on the percent of saturation of the biocide in the solution rather than on its total concentration in the formulation.1 Therefore, the percent saturation of phenolic biocides, including triclosan, is a key variable affecting antibacterial efficacy of a formulation. A higher saturation solubility or total concentration of the phenolic biocide i.e., triclosan) affects the kinetics of bacterial kill, leading to greater bacterial reductions at shorter contact times.
This research led to a formulation technology that activates triclosan to a high-saturation solubility and total concentration level, allowing bacterial kill at shorter contact times for the microorganism.2 Called activated triclosan, the technology was granted a patent by the U.S. Patent and Trademark Office in 2000.
Comparisons of Effectiveness
To evaluate the effectiveness and activity level of this new activated triclosan technology, it was tested against a U.S. Food and Drug Administration (FDA)-recommended control formulation of a well known 4-percent CHG. The test was conducted by an independent laboratory, Hilltop Research Laboratories Inc., using ASMT E-1174-00 Standard Test Method for Evaluation of the Effectiveness of Healthcare Personnel or Consumer Handwash Formulations.
By way of definition and comparison purposes, in a tentative final monograph (June 17, 1994), the FDA requires a 10-2 reduction of the marker organism on each hand within five minutes following product treatments after the first wash and a 10-3 reduction after the 10th wash. The FDA also recommends the use of a 4-percent CHG as the healthcare personnel handwash reference control formulation when measuring the effectiveness of log reductions of other handwash or handrinse formulations.
The marker organism in this study, which included a total of 46 subjects, was Serratia marcescens. During a one-week washout period, all subjects refrained from using any products containing antimicrobials. On test day, the subjects' hands were contaminated with Serratia marcescens (ATCC 14756) as a marker organism and a base sampling was performed. Following washing with the new test product (triclosan at 0.45 percent target level) during treatments one through 10, subjects' hands were sampled for post treatment count, enumerated for recovery of Serratia marcescens, and compared to the recovery results obtained with 4-percent CHG. The results of the new activated triclosan formulation (0.45 percent) against the standard control brand (4-percent CHG) formulation are as follows:
Discussion and Results
This data indicates that the breakthrough formulation of activated triclosan (0.45 percent) is significantly more effective in initial log reduction after the first handwash and has similar activity after the 10th handwash as the control hand wash brand of 4-percent CHG. Most triclosan-based products and other active ingredients have not been formulated to impart efficacy comparable to a 4-percent CHG formulation in either initial log reduction of microorganisms after the first wash or after the 10th.
The Importance of Aseptic Hands With Clean Skin
Establishing and maintaining aseptic skin conditions discourages transient pathogenic microorganisms from becoming opportunistic or transient by hitchhiking from surface to surface during the patient care day. Handwashing with an efficacious healthcare professional handwash (HCPHW) formulation should be successful in removing organic soil loads and be effective in log reduction activity after the first wash episode, while maintaining efficacy after continued use during the patient-care day. Infection control professionals (ICPs) have documented that handwashing is the single most important control point in any hospital or nursing home infection control program. To be able to obtain the conditions of aseptic skin conditions requires proper handwashing techniques by nursing staff, physicians, related healthcare professionals and patients.4-6
Removing organic soil loads from the hands is an important benefit when using a HCPHW. The presence of invisible and visible organic soil loads enhances the probability of pathogenic microorganisms becoming opportunistic and transient. One Pseudomonas aeruginosa bacteria, given the right conditions and doubling every 20 minutes, can multiply to more than 1 billion in just 10 hours without being detected by the human eye. Existing organic soils on hands provide an ideal environment for opportunistic transient microorganisms to survive.
Waterless Alcohol Gel Hand Rinse Supplements
The use of waterless alcohol gel hand rinses has increased significantly within healthcare settings due to the availability of a wide array of products in convenient-to-use dispensers. Being waterless, the antimicrobial hand rinse can be used without rinsing the hands at a sink -- a significant time saver during a hectic caregiver day. A survey of published research indicates that alcohol, in appropriate concentrations, provides rapid initial log reduction of microorganisms on the hands of the caregiver when compared to other active ingredients.7-10
It is suggested that the use of waterless alcohol gel hand rinses with convenient, wall-mounted, in-room dispensers probably increases frequency of handwash compliance during pre- and post-patient care. It can also be surmised that in many instances, waterless alcohol gel hand rinses are replacing the use of plain soap and water for handwashing, which can be seen as a positive development. Guidelines from the Association for Professionals in Infection Control and Epidemiology (APIC) suggest that alcohol-based hand rinses have excellent initial log reduction ability against most gram-negative and gram-positive microorganisms including activity against many viruses and fungi such as HIV, hepatitis B and tubercle bacillus.11
However, Elaine Larson, professor of pharmaceutical and therapeutics research at the Columbia University School of Nursing, suggests alcohol as an active ingredient is not an effective cleaning agent in removing organic soils from the hands. This is one reason for the suggestion that waterless alcohol gels be used as a supplement to a regular HCPHW, not as a replacement. The regular use of a HCPHW enhances friction removal of existing organic soil loads, and the rinsing of caregiver hands is an important element in this removal process. Other alcohol-related concerns cited by Larson and other published research include skin drying (depending on the formulation) and evidence that some formulations strip the skin of essential oils that act as a natural barrier to microorganism invasion of the epidermis. While Larson and others rank alcohol as "excellent" in initial log reduction of microorganisms, alcohol as an active ingredient is not sporicidal to microorganism spores and has little or no persistent activity over time.12
Other published research findings verify that alcohol as an active ingredient effectively achieves an excellent initial log reduction level. Paulson, et al., publishing in Dairy, Food and Environmental Sanitation, also found improved persistent log reduction with a marker organism when using a waterless alcohol gel daily hand as a supplement to a HCPHW.13-14 Additional conclusions by Paulson and others support the position that waterless alcohol gel, while achieving excellent initial reduction of transient opportunistic microorganisms, has little or no persistence activity over time and even loses some of its log reduction capability after the seventh or the 10th handwash episode.15 This becomes more significant when one considers that caregivers wear latex gloves during patient-handling episodes. Over time, wearing latex gloves can promote a warm, moist epidermal surface environment on hands. A warm and moist skin surface with organic soil loads is an ideal environment to encourage the growth of microorganisms during the patient-care day. Given that alcohol is not sporicidal, is not a good cleaning agent, and has limited or no persistent activity over time against microorganisms, the widespread use of alcohol gel hand rinses in place of a healthcare personnel hand wash should be reevaluated. To maintain effective infection control standards, the hospital should use a highly effective HCPHW as the base handwash solution to clean the hands of visible and invisible organic soils. This also provides excellent initial log reduction of microorganisms and maintains effectiveness through repeated handwash episodes. Waterless alcohol gels should then be used as a convenient supplement to an effective HCPHW to achieve a successful handwashing regimen and maintain aseptic skin conditions throughout the caregiver day.
The new activated triclosan formulation tested as superior to 4-percent CHG in initial log reduction and is equal in effectiveness over time to a well known 4-percent CHG brand. It is formulated in a surfactant solution, which enables it to be successful at cleaning organic soil loads from the skin, and has demonstrated low potential for skin irritation. It is this type of unique formulation that will enable an institution to have a mild handwash solution with superior efficacy, while still using a waterless alcohol gel to complete the handwashing protocol as part of a comprehensive infection control program. Triclosan has been tested in concentrations of 0.3 percent to 2.0 percent and found to be effective and safe, and it maintains persistent activity over time even in the presence of organic materials and soil loads.16-17 In its newest form, triclosan offers the benefit of being as or more effective as a 4-percent CHG formulation in both initial log reduction and after repeated use.
Thomas Kovach is president of Kovach & Associates Inc., a general management-consulting firm that specializes in handwashing, infection control, skin care and wound care topics.
|After WASH #1||After WASH #10|
|Activated Triclosan (0.45 %)||3.47||3.58*|