Reproducibility and Workability of the European Test Standard EN 12791 Regarding the Effectiveness of Surgical Hand Antiseptics A Randomized, Multicenter Trial

Alcohol-Based Chlorhexidine and Potassium Sorbate Rub Strengthens the Effectiveness of Traditional Hand Scrubbing and Improves Long-Lasting Effectiveness-Evaluation of Hand Preparation Protocols According to EN 12791

Despite the advantages of surgical handrub in terms of the ease of application and effectiveness, chlorhexidine (CHG)-based hand scrubbing remains the preferred method for surgical hand preparation. However, it does not systematically meet the non-inferiority requirement of the European norm (EN) 12791 with respect to n-propanol (the reference product) and does not provide the sustained efficacy expected for these long-lasting agents. Commercially available alcohol-based products have also failed to demonstrate sustained efficacy according to EN 12791. Multi-step protocols enhance the efficacy of hand scrubbing, yet their extended disinfection duration might diminish their allure for healthcare professionals. In this study, we show that hand scrubbing with CHG 4% followed by a 1 min rubbing with the novel formulation of ethanol (Et) 70%/CHG 3% plus 0.3% potassium sorbate food additive (PS) meets the non-inferiority requirement and demonstrates sustained efficacy when tested according to EN 12791. The immediate and 3 h effect of this protocol was significantly higher than that of n-propanol and the homologous disinfection protocol without PS (CHG 4% hand scrub plus Et 70%/CHG 3% rub), demonstrating that the inclusion of PS confers a notable residual effect. We speculate that this non-volatile ingredient acts synergistically with CHG. This promising combination represents an alternative method for the development of new disinfection strategies.

Surgical hand preparation with chlorhexidine soap or povidone iodine: new methods to increase immediate and residual effectiveness, and provide a safe alternative to alcohol solutions

BACKGROUND

Surgical use of 4% chlorhexidine soap (CHX-4) and 10% povidone iodine (PVP-I-10) does not meet the standards defined by EN 12791.

AIM

To investigate the possibility of increasing the immediate and residual effects of these antiseptics.

METHODS

Over three consecutive weeks, n-propanol, standard CHX-4 and PVP-I-10 were tested in two experimental groups of volunteers. The new method for applying the antiseptic substances involved standard hand rub and rinse of CHX-4 or PVP-I-10, followed by application of an aqueous solution based on 5% chlorhexidine or PVP-I-10 with no further rinsing of the hands prior to donning gloves. Samples were taken to assess immediate and residual effects, analysing the logarithmic reduction of colony-forming units.

FINDINGS

At t=0 h, n-propanol was superior in bactericidal effect to standard CHX-4 (P<0.05), but the new chlorhexidine protocol was superior to both standard CHX-4 (P<0.01) and n-propanol (P<0.05); the same effect was observed at t=3 h (residual effect). At t=0 h, n-propanol was significantly superior to standard PVP-I-10, but the new PVP-I-10 protocol was superior, although not significantly, to n-propanol. There was no significant residual effect at t=3 h.

CONCLUSION

The new protocol for chlorhexidine application permits surgical hand preparation with chlorhexidine, as a safe alternative to alcohol solutions, because it meets the standards defined by EN 12791.

Chlorhexidine is not an essential component in alcohol-based surgical hand preparation: a comparative study of two handrubs based on a modified EN 12791 test protocol

BACKGROUND

Surgical hand preparation is an essential part of modern surgery. Both alcohol-based and antiseptic detergent-based hand preparation are recommended practices, with a trend towards use of alcohol based handrubs. However, discussion has arisen whether chlorhexidine is a required ingredient in highly efficacious alcohol-based formulations, in view of providing sustained antimicrobial efficacy.

METHODS

One alcohol-only formulation (product A), containing ethanol and n-propanol, and one formulation containing a chlorhexidine-ethanol combination (product B) were directly compared with each other using a modified test protocol based on European standard EN 12791 (2016) with 25 volunteers. The alcohol-only formulation (product A) was applied for only 90 s, the chlorhexidine-alcohol formulation (product B) for 180 s. Microbial log reduction factors were determined and statistically compared immediately after application and at 6 h under surgical gloves.

RESULTS

The alcohol-only formulation (product A) achieved mean log reduction factors of 1.96 ± 1.06 immediately after application and 1.67 ± 0.71 after 6 h. The chlorhexidine-alcohol combination (product B) achieved mean log reduction factors of 1.42 ± 0.79 and 1.24 ± 0.90 immediately and after 6 h, respectively. The values for product A were significantly greater than those for product B at both measured time points (p ≤ 0.025 immediately after application and p ≤ 0.01 after 6 h).

CONCLUSIONS

An optimized alcohol-only formulation tested according to a modified EN 12791 protocol in 25 healthy volunteers outperformed a chlorhexidine-alcohol formulation both immediately after application and at 6 h under surgical gloves, despite a much shorter application time. Thus, optimized alcohol-only formulations do not require chlorhexidine to achieve potent immediate and sustained efficacy. In conclusion, chlorhexidine is not an essential component for alcohol-based surgical hand preparation.

Surgical hand antisepsis to reduce surgical site infection

BACKGROUND

Medical professionals routinely carry out surgical hand antisepsis before undertaking invasive procedures to destroy transient micro-organisms and inhibit the growth of resident micro-organisms. Antisepsis may reduce the risk of surgical site infections (SSIs) in patients.

OBJECTIVES

To assess the effects of surgical hand antisepsis on preventing surgical site infections (SSIs) in patients treated in any setting. The secondary objective is to determine the effects of surgical hand antisepsis on the numbers of colony-forming units (CFUs) of bacteria on the hands of the surgical team.

SEARCH METHODS

In June 2015 for this update, we searched: The Cochrane Wounds Group Specialized Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations) and EBSCO CINAHL. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials comparing surgical hand antisepsis of varying duration, methods and antiseptic solutions.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed studies for inclusion and trial quality and extracted data.

MAIN RESULTS

Fourteen trials were included in the updated review. Four trials reported the primary outcome, rates of SSIs, while 10 trials reported number of CFUs but not SSI rates. In general studies were small, and some did not present data or analyses that could be easily interpreted or related to clinical outcomes. These factors reduced the quality of the evidence. SSIsOne study randomised 3317 participants to basic hand hygiene (soap and water) versus an alcohol rub plus additional hydrogen peroxide. There was no clear evidence of a difference in the risk of SSI (risk ratio (RR) 0.97, 95% CI 0.77 to 1.23, moderate quality evidence downgraded for imprecision).One study (500 participants) compared alcohol-only rub versus an aqueous scrub and found no clear evidence of a difference in the risk of SSI (RR 0.56, 95% CI 0.23 to 1.34, very low quality evidence downgraded for imprecision and risk of bias).One study (4387 participants) compared alcohol rubs with additional active ingredients versus aqueous scrubs and found no clear evidence of a difference in SSI (RR 1.02, 95% CI 0.70 to 1.48, low quality evidence downgraded for imprecision and risk of bias).One study (100 participants) compared an alcohol rub with an additional ingredient versus an aqueous scrub with a brush and found no evidence of a difference in SSI (RR 0.50, 95% CI 0.05 to 5.34, low quality evidence downgraded for imprecision). CFUsThe review presents results for a number of comparisons; key findings include the following.Four studies compared different aqueous scrubs in reducing CFUs on hands.Three studies found chlorhexidine gluconate scrubs resulted in fewer CFUs than povidone iodine scrubs immediately after scrubbing, 2 hours after the initial scrub and 2 hours after subsequent scrubbing. All evidence was low or very low quality, with downgrading typically for imprecision and indirectness of outcome. One trial comparing a chlorhexidine gluconate scrub versus a povidone iodine plus triclosan scrub found no clear evidence of a difference-this was very low quality evidence (downgraded for risk of bias, imprecision and indirectness of outcome).Four studies compared aqueous scrubs versus alcohol rubs containing additional active ingredients and reported CFUs. In three comparisons there was evidence of fewer CFUs after using alcohol rubs with additional active ingredients (moderate or very low quality evidence downgraded for imprecision and indirectness of outcome). Evidence from one study suggested that an aqueous scrub was more effective in reducing CFUs than an alcohol rub containing additional ingredients, but this was very low quality evidence downgraded for imprecision and indirectness of outcome.Evidence for the effectiveness of different scrub durations varied. Four studies compared the effect of different durations of scrubs and rubs on the number of CFUs on hands. There was evidence that a 3 minute scrub reduced the number of CFUs compared with a 2 minute scrub (very low quality evidence downgraded for imprecision and indirectness of outcome). Data on other comparisons were not consistent, and interpretation was difficult. All further evidence was low or very low quality (typically downgraded for imprecision and indirectness).One study compared the effectiveness of using nail brushes and nail picks under running water prior to a chlorhexidine scrub on the number of CFUs on hands. It was unclear whether there was a difference in the effectiveness of these different techniques in terms of the number of CFUs remaining on hands (very low quality evidence downgraded due to imprecision and indirectness).

AUTHORS' CONCLUSIONS

There is no firm evidence that one type of hand antisepsis is better than another in reducing SSIs. Chlorhexidine gluconate scrubs may reduce the number of CFUs on hands compared with povidone iodine scrubs; however, the clinical relevance of this surrogate outcome is unclear. Alcohol rubs with additional antiseptic ingredients may reduce CFUs compared with aqueous scrubs. With regard to duration of hand antisepsis, a 3 minute initial scrub reduced CFUs on the hand compared with a 2 minute scrub, but this was very low quality evidence, and findings about a longer initial scrub and subsequent scrub durations are not consistent. It is unclear whether nail picks and brushes have a differential impact on the number of CFUs remaining on the hand. Generally, almost all evidence available to inform decisions about hand antisepsis approaches that were explored here were informed by low or very low quality evidence.

Lasting hand self-disinfection: A backup for hospital hand hygiene?

BACKGROUND

Hand disinfection should be performed on the occasion of 5 separate moments during patient care, but some occasions are skipped. Can using hand antiseptics with residual effect reduce the problem of infection spread? We evaluated a 30-minute residual effect by different antiseptic products on endogenous and acquired microbiota.

METHODS

The products tested were 2% and 5% chlorhexidine, 1% and 10% iodine povidone, 60° n-propanol, 0.2% mecetronium + isopropanol, and 0.6% chlorhexidine + isopropanol + 0.1% benzalconium chloride. The microorganisms identified were 3 ATCC and 9 multiresistant strains isolated from intensive care unit patients (used as acquired microbiota). Logarithmic (log10) reductions of the colony forming units obtained with each antiseptic product and for each microorganism were calculated via in vivo (6 volunteers) and in vitro tests.

RESULTS

The better in vivo and in vitro products with a residual effect > 2 log10 after 30 minutes on hands were 2%-5% chlorhexidine and 0.6% chlorhexidine + isopropanol + 0.1% benzalconium chloride. This reduction was significantly different (P < .01) from the other 4 antiseptics. This residual effect (> 2 log10) can be considered a self-disinfecting hand status in daily practice.

CONCLUSIONS

Hand antiseptics used in hospitals must pass tests of residual efficacy (after 30 minutes on acquired microbiota) showing a reduction > 2 log10 in vivo and in vitro. A good product can be the mixture of chlorhexidine + alcohol + benzalconium chloride.

Efficacy of 2 Alcohol-Based Gels and 1 Alcohol-Based Rinse for Surgical Hand Disinfection

We assessed the efficacy of 2 alcohol-based gels and 1 alcohol-based rinse for surgical hand disinfection, using European standard EN 12791. Volunteers performed surgical hand disinfection with a reference product and each of the 3 study products, with 1-week intervals between disinfection episodes. The immediate and sustained antimicrobial activities of each study product were not significantly less than those of the reference product. The study products passed the efficacy requirements of the EN 12791 standard, and they are considered suitable for surgical hand disinfection.

Surgical Hand Antisepsis With Alcohol-Based Hand Rub Comparison of Effectiveness After 1.5 and 3 Minutes of Application

Objective.

Research has shown 1.5 minutes of surgical hand antisepsis with alcohol-based hand rub to be at least as effective under experimental conditions as the 3-minute reference disinfection recommended by European Norm 12791. The aim of the present study was to validate the effectiveness of 1.5 minutes of surgical hand antisepsis in a clinical setting by comparing the effectiveness of 1.5- and 3-minute applications of alcohol-based hand rub (45% vol/vol 2-propanol, 30% vol/vol 1-propanol, and 0.2% mecetronium ethylsulphate).

Design.

Prospective crossover trial in which each surgeon served as his or her own control, with individual randomization to the 1.5-or the 3-minute group during the first part of the trial.

Setting.

Basel University Hospital, Switzerland.

Participants.

Thirty-two surgeons with different levels of postdoctoral training.

Methods.

We measured the bactericidal effectiveness of 1.5 minutes and 3 minutes of surgical hand antisepsis with alcohol-based hand rub by assessing the mean (± SD) log10 number of colony-forming units before the application of hand rub (baseline), after the application of hand rub (immediate effect), and after surgery (sustained effect) so as to follow European Norm 12791 as closely as possible.

Results.

The immediate mean (± SD) log10 reduction in colony-forming units (cfu) was 2.66 ±1.13 log10 cfu for the 1.5-minute group and 3.01 ±1.06 log10 cfu for the 3-minute group (P = .204). Similarly, there was no statistically significant difference between the 2 groups with respect to the sustained effect; the mean ( ± SD) log10 increase in bacterial density during surgery was 1.08 ± 1.13 log10 cfu for the 1.5-minute group and 0.95 ± 1.27 log10 cfu for the 3-minute group (P = .708). No adverse effects were recorded.

Conclusion.

In this clinical trial, surgical hand antisepsis with alcohol-based hand rub resulted in a similar bacterial reduction, regardless of whether it was applied for 3 or 1.5 minutes, which confirms experimental data generated with healthy volunteers.

Modified World Health Organization hand rub formulations comply with European efficacy requirements for preoperative surgical hand preparations

BACKGROUND

The World Health Organization (WHO) has published "Guidelines on Hand Hygiene in Health Care" recommending 2 hand rub formulations based on 80% vol/vol ethanol or 75% vol/vol isopropanol for local production in healthcare settings where commercial products are not available or are too expensive. Previous investigations have shown that neither formulation meets the efficacy requirements of European norm (EN) 12791, which is the most stringent available norm for surgical hand rub preparations. Even when modified with approximately 5% higher alcohol content, the formulations proved to be inferior to the reference of the norm when measured after 3 hours.

OBJECTIVE

Because the high glycerol content of the formulations was suspected to negatively influence their efficacy, additional investigations were performed with varying glycerol content.

METHODS

Modified formulations with higher alcohol concentration (mass instead of volume percentage) and lower glycerol concentration (0.725% instead of 1.45%) or without the addition of glycerol were evaluated for their conformity with the efficacy requirements of EN 12791, which demands noninferiority in comparison with a reference hand antisepsis procedure immediately and 3 hours after treatment on volunteers' hands.

DESIGN

Randomized Latin-square design.

SETTING

Microbiology laboratory of the Medical University of Vienna, Vienna, Austria.

PARTICIPANTS

Twenty-five healthy volunteers.

RESULTS

Reducing the concentration of glycerol or omitting it completely rendered both WHO formulations noninferior to the reference, both immediately and 3 hours after surgical hand antisepsis.

CONCLUSIONS

Both WHO-recommended formulations meet the efficacy requirements of EN 12791 by increasing their alcohol concentrations by 5%, prolonging their application to 5 minutes and reducing the glycerol concentration to 0.725%.

Determination of antiseptic efficacy of rubs on the forearm and consequences for surgical hand disinfection

While hands are acknowledged to be the most important source of pathogens from the skin of the surgical team, the transmission of pathogens from the forearms may also be relevant. Preoperative hand disinfection is recommended, but evidence-based standards for the forearms are lacking. As neither the European standard EN 12791 nor the American guidelines ASTM 1115 are applicable to the forearms, a new test method based on the European standard EN 12791 and the German Society for Hygiene and Microbiology (DGHM) method for testing for the efficacy of skin antiseptics was developed to address the forearms. The antiseptic efficacy of a commercially available alcohol-based hand rub [76.7% (w/w) ethanol] was assessed on the upper arm after 15s, 2.5 min, and 30 min, and on the lower arm after 2.5 min, 30 min, and 3 h. On the upper arm, application of the product followed the DGHM standard procedure. On the forearm, the product was applied by the participants themselves with the right hand over the left forearm and vice versa as performed during preoperative hand disinfection. Sampling and culture were performed according to the DGHM method for skin antisepsis on the upper arm. Twenty-two volunteers were investigated. The efficacy of the antiseptic treatment on the forearm was not significantly lower than on the upper arm for any of the areas tested (P > 0.05). Reduction factors for all tested areas and times were quite similar, with confidence intervals ranging between 1.43 and 2.31 log₁₀. We suggest that an application time of 10s may be sufficient for the treatment of the forearm as part of preoperative hand disinfection, provided that an appropriate product is used.

Surgical hand rub: Influence of duration of application on the immediate and 3-hours effects of n-propanol and isopropanol

BACKGROUND

The recommended duration for surgical hand treatment has been changed from 10 over 5 to 3 minutes and even shorter.

OBJECTIVES

Our objective was to study the impact of the length of surgical hand antisepsis with n-propanol 60% (vol/vol) or isopropanol 70% (vol/vol) applied for 1, 3, or 5 minutes on the reduction of resident hand flora in the setting of the microbiologic laboratory for experimental and applied testing of disinfectants and antiseptics at the Medical University Vienna, Austria, using a Latin Square design.

METHODS

Our methods were according to the Austrian Guidelines for Testing Products for Surgical Hand Antisepsis. The release of bacterial hand flora of 21 subjects is assessed before and immediately after disinfection from one hand and 3 hours later from the other, meanwhile gloved, hand. Mean reduction factors (RF) are calculated.

RESULTS

The immediate mean log(10) RFs with n-propanol or isopropanol were 1.05, 2.03, and 2.30 and 0.74, 1.48, and 2.12, respectively, when applied for 1, 3, or 5 minutes, respectively. After 3 hours, the respective mean log(10) RFs were 0.45, 1.01, and 1.60 and 0.19, 0.79, and 1.03. Thus, with increasing length of application, a highly significant trend (P < .001) toward higher log(10) reductions was demonstrated. At both sampling times, n-propanol was more effective than isopropanol at the corresponding treatments. Furthermore, a highly significant (P < .001) association was found between the individual volunteers and the effect of the antiseptics on their hands.

CONCLUSION

The efficacy of surgical antisepsis is significantly associated with the length of application.

Improving adherence to surgical hand preparation

At present, no universal agreement on detailed practice for surgical hand preparation exists. In order to fill this gap, in 2002 a Franco-German recommendation for surgical hand preparation was published as a first step towards a generally accepted European recommendation. Based on an assessment of the actual literature, a protocol for surgical hand preparation is discussed with the aim to recommend evidence-based standard procedures including prerequisites, washing and disinfection phase, and its practical implementation. In contrast to hygienic hand disinfection, for surgical hand preparation compliance is not an issue, since it mostly is regarded as a ceremony which is carried out without exception. Nevertheless, the following factors influence acceptance and efficacy: skin tolerance, ease of use, duration of procedure, and recommended time), potential for impaired efficacy due to incorrect performance of the procedure, possibility of systemic risks and irritating potential by applied preparations, religious restrictions, ecological aspects, costs and safety. Here, we report our experience with the introduction of a new hand preparation regime in all surgical disciplines in our university hospital based on the above factors. The following statements were evaluated: 1) The immediate efficacy of an alcohol-based hand disinfectant is impaired by a preceding hand wash for up to 10 minutes. Therefore hands should not be routinely washed before the disinfection period unless there is a good reason for it such as visible soiling. 2) A shortened application time (1.5 minutes) is equal to 3 min in terms of efficacy. 3) Hands should be air dried before gloves are put on, otherwise the perforation rate of gloves will increase. 4) The efficacy of alcohol-based disinfectants is significantly higher when hands are allowed to dry for 1 minute after the washing phase and before the disinfection phase. To clarify the above questions before the establishment of the modified technique, the surgical team was invited to a meeting. As a result, the heads of surgical departments supported the new technique and decided to change their practice.

Does Preoperative Topical Antimicrobial Scrub Reduce Positive Surgical Site Culture Rates in Men Undergoing Artificial Urinary Sphincter Placement?

PURPOSE

We determined if the incidence of a perioperative surgical site-positive culture was reduced by a 5-day topical antimicrobial scrub before implantation of an artificial urinary sphincter.

MATERIALS AND METHODS

A single surgeon prospective cohort study was conducted of 100 consecutive artificial urinary sphincter implants placed between May 2003 and November 2005. We compared 50 men who performed preoperative topical antimicrobial scrub with 4% chlorhexidine to the abdominal site and perineal site with 50 men who used their normal hygiene (soap and water). All received povidone-iodine skin disinfection before incision, and bacterial cultures of the abdominal and perineal sites were collected immediately after skin disinfection and after artificial urinary sphincter implantation. Baseline comparisons between groups were done with the Wilcoxon rank sum and Fisher exact tests. Predictors of positive culture were identified using multivariate logistic regression analysis.

RESULTS

The causes of incontinence were radical prostatectomy (90), radiation therapy (8) and transurethral resection of the prostate (2). There were no baseline differences between the groups including age, diabetes or previous urethral surgery. Overall 140 of the 400 cultures were positive with only 37% of the positive cultures (52 of 140) observed with topical antimicrobial scrub. For the perineal site the only factor affecting preoperative culture status was topical antimicrobial scrub (OR 0.23, p = 0.003). A positive postoperative culture was predicted by a positive preoperative perineal (OR 4.61, p = 0.003) and abdominal culture (OR 3.80, p = 0.013).

CONCLUSIONS

Preoperative topical antimicrobial scrub resulted in a 4-fold reduction in preoperative perineal colonization rate and overall reduction in positive surgical site cultures. Given the low cost, safety and efficacy, topical antimicrobial scrub should be considered before artificial urinary sphincter placement.