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
Hennig et al. Antimicrobial Resistance and Infection Control
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
Thomas-Jörg Hennig 0
Sebastian Werner 1
Kathrin Naujox 1
Andreas Arndt 0
0 B. Braun Medical AG, Centre of Excellence Infection Control , Seesatz 17, 6204 Sempach , Switzerland
1 HygCen Germany GmbH , Bornhövedstrasse 78, 19055 Schwerin , Germany
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; Surgical scrubbing; Chlorhexidine; Alcohol; Handrub evaluation
Surgical hand preparation, also termed surgical hand
antisepsis or surgical scrubbing, has become an essential part
of modern surgery. It was introduced as part of the
postListerian system of aseptic surgery that was widely
adopted in Europe and the USA at the turn of the
twentieth century [
]. The goal of surgical hand preparation is to
generate a near-elimination of transient hand flora or
hand contamination, and a substantial reduction of
resident hand flora that would be sustained for the duration
of the surgery [
]. The aim is to prevent wound
contamination or infection by accidental glove leaks or glove
rupture. Although the basic necessity of surgical hand
preparation, as compared to no preparation, has never
been tested in a randomized clinical trial (RCT), the
practice is nevertheless strongly supported by the principles of
microbiology, by existing models of pathogen
transmission and by empirical observations. Hands are frequently
contaminated with microorganisms, accidental sterile
glove leaks are common and there are observations of
case clusters of surgical infections when hand preparation
protocols were inadequate or breached [
The two main approaches to surgical hand preparation
are (a) aqueous preparation, using antiseptics such as
chlorhexidine (CHG) or povidone-iodine (PVI) in a
detergent base that are applied and then rinsed off with
running water, and (b) preparation with alcohol-based
handrubs, without rinsing with water, where the alcohol
provides the bulk of the microbicidal action. The
preference for either of the two approaches differs in different
healthcare settings, and both aqueous and alcohol-based
hand preparation have been incorporated as suitable
alternatives into important major guidelines [
2, 6, 7
Alcohol-based hand preparation has four main
advantages over aqueous preparation, (a) it generally achieves
much greater reduction of microorganisms on hands, (b)
formulations with suitable emollients are usually
associated with less skin damage and dermatitis, (c) it requires
shorter application times, and (d) it saves considerable
amounts of running water [
2, 3, 8, 9
]. One large RCT of
alcohol-based versus aqueous preparation found
equivalence in terms of surgical site infection (SSI) rates and
concluded that the alcohol-based protocol was better
tolerated by the surgical teams and improved
compliance with hand hygiene guidelines . Modern
alcohol-based handrub formulations can meet efficacy
requirements within application times as short as
1.5 min, which can translate to time savings for surgeons
and surgical teams [
The efficacy of surgical hand preparation
formulations and protocols is routinely tested using
standardized in vivo microbiological protocols on the hands of
]. The European standard EN 12791 [
compares a given formulation to a reference alcohol
consisting of 60% (v/v) n-propanol on clean hands
and stipulates that the microbial log reduction
factors of the tested formulation must not be
statistically inferior to the reference, both immediately after
application and after 3 h under surgical gloves. The
US standard ASTM E1115 [
], applied with the US
Food and Drug Administration (FDA) criteria [
stipulates that a given formulation on clean hands
must achieve absolute microbial log reduction factors
of 1.0 on the first day of application, of 2.0 on the
second day, and of 3.0 on the fifth day after a total
of 11 sequential applications, and must show
sustained efficacy by way of microbial counts not
exceeding those at baseline after 6 h under surgical
gloves. Both standards require that
adequatelyvalidated neutralizers are used during testing, in
order to prevent false-positive results from sustained
antimicrobial activity that is exerted after the end of
the planned antiseptic exposure [
Discussion has arisen as to whether alcohol-based
surgical handrubs should contain CHG as a second agent,
to ensure persistency of the antiseptic effects for the
duration of the operation. A few studies [
reported superiority of CHG-alcohol combination rubs
over alcohol-only products at time points of up to 6 h
under surgical gloves. However, concerns were
subsequently raised about methodological details of these
studies, such as whether initial antiseptic application and
subsequent neutralization were adequate [
order to investigate this question further, we initiated a
comparative study of an alcohol-only versus a
CHGalcohol combination handrub, based on a modified EN
12791 test protocol with an extended period of 6 h
under surgical gloves.
Two commercially available alcohol-based handrubs
were investigated. Product A was an alcohol-only
handrub containing 45% (w/v) ethanol, 18% (w/v)
npropanol and emollients (Softa-Man®, also branded as
Softalind®, B. Braun, Sempach, Switzerland). Product B
was a CHG-alcohol combination handrub containing 1%
(w/w) chlorhexidine gluconate, 61% (w/w) ethanol and
emollients (3 M™ Avagard™ Surgical and Healthcare
Personnel Hand Antiseptic with Moisturizers, 3 M
Health Care, St. Paul, MN, USA).
Twenty-five healthy volunteers were included in two
experimental runs in a randomized, cross-over design
according to a modified EN 12791 protocol [
two modifications were that instead of using 60% (v/v)
n-propanol as a reference, the two products (A and B)
were directly compared as part of a benchmarking
exercise, and that a prolonged period of 6 h instead of
3 h under surgical gloves was used to assess sustained
efficacy. Hands were prewashed for 1 min with
nonantiseptic soap. Pretreatment bacterial counts
(prevalues) were obtained by rubbing fingertips and thumb
tips in 10 ml tryptic soy broth (TSB) for 1 min.
Subsequently, each subject used either product A or product
B by applying 3 portions of 3 ml of the product to the
hands, in such a way as to keep the hands moist with
the product for the duration of the application.
Product A was applied for a shortened application time of
90 s, product B was applied for the full 3 min duration,
as usually done for the reference alcohol in EN 12791.
Immediate postexposure bacterial counts (first
postvalues) were taken from one hand by rubbing fingertips
and thumb tips in 10 ml TSB containing neutralizers,
and the other hand remained gloved for 6 h. Another
set of bacterial counts (second postvalues) was taken
after glove removal. Validated neutralizers (a
combination of 5.0% polysorbate 80 + 0.6% sodium oleate
+2.0% lecithine) according to EN 13727 [
] were used
in the TSB for sampling (postvalues). Samples in TSB
were plated on neutralizer-free tryptic soy agar (TSA),
incubated at 36+/−1 °C for 48 h, and colonies were
subsequently enumerated. The differences between the
log10 pre- and postvalues (log reduction factors) were
determined for each subject, and the means of these
differences were statistically compared using the
Wilcoxon matched-pairs signed-ranks test.
The results of the direct comparison between the
alcohol-only (product A) versus the CHG-alcohol
(product B) handrub are shown in Table 1. Product A
achieved mean log reduction factors (± standard
deviation) of 1.96 ± 1.06 immediately after application, and
1.67 ± 0.71 after 6 h. Product B achieved mean log
reduction factors of 1.42 ± 0.79 and 1.24 ± 0.90
immediately and after 6 h, respectively. The mean log
reduction factors obtained with use of product A were
significantly greater than those of product B at both
time points, immediately after application (p ≤ 0.025)
and after 6 h under surgical gloves (p ≤ 0.01).
Our results show that an alcohol-only handrub that
contains an optimized composition of two alcohol
species, ethanol and n-propanol, achieved a significantly
greater initial microbial reduction after surgical hand
preparation than a CHG-alcohol combination handrub
when tested according to a modified EN 12791
protocol, and that a significant difference in reduction
factors in favor of the alcohol-only rub was maintained
for 6 h under surgical gloves. These results are
consistent with findings from a previous comparative study
], in which an 80% (w/w) ethanol-only rub passed
EN 12791 requirements both immediately and at 3 h
after application, while the same 1% (w/w) CHG and
61% (w/w) ethanol combination rub as was used in the
present study failed at both time points. Among the
three common alcohol species (ethanol, isopropanol
and n-propanol) that are used for hand and skin
antisepsis, n-propanol has the most potent general
microbicidal activity and exerts this at relatively lower
]. This supports its inclusion into
alcohol-based handrubs and explains the potent
activity exhibited by a combination of n-propanol and
ethanol at an overall concentration of 63% (w/v) in product
A as observed in the present study.
The results in this study were obtained despite the
absence of CHG in handrub A, despite the extended
test interval of 6 h under surgical gloves and despite
the fact that handrub B was given a very substantial
a priori advantage by having had twice the initial
application time (180 s) of handrub A (90 s), with the
application volume (3 × 3 ml) and other conditions
being equal. These findings are consistent with
earlier findings indicating that the application of
alcohols, despite the absence of residual activity per se,
is followed by substantially delayed regrowth of skin
flora or even continued microbial killing [
that the contribution of dedicated supplements for
persistency is relatively modest or even absent when
tested for durations of up to 6 h [
]. This is
further consistent with the concept that an initially
strong and immediate microbial killing capacity
RF reduction factor, SD standard deviation, CHG chlorhexidine
aCalculated using the Wilcoxon matched-pairs signed-ranks test
continues to translate into low viable microorganism
numbers for several hours under surgical gloves. The
extended duration of 6 h under surgical gloves was
chosen for the present experiments, instead of the
usual 3 h for EN 12791, in order to simulate tougher
test conditions that resemble those of the US ASTM
E1115 standard in this aspect. Furthermore, our
results as well as those of others [
shorter application times, as short as 1.5–2 min,
when highly potent alcohol-based handrubs are used.
In addition to using an effective alcohol-based
handrub, the technique of application is also considered
]. While EN 12791 requires coverage of
only the hand surfaces for the purpose of efficacy
testing, the World Health Organization hand hygiene
] state that complete coverage of hands
and forearms requires about 15 ml (about 3 × 5 ml)
and emphasize that it is important to keep hands and
forearms wet with alcohol for the entire duration of
application. Some protocols that include very small
applied volumes [
] are therefore a cause for concern,
as they are likely to lead to incomplete skin surface
coverage and interrupted action of the antiseptic.
In the area of skin antisepsis, CHG has been the
subject of a considerable amount of incorrect assessment.
What had happened was that a substantial proportion of
the clinical trial-based literature on skin antisepsis had
attributed favorable clinical outcomes achieved with
CHG-alcohol combinations (two effective antiseptics) to
CHG alone and concluded that CHG alone (instead of
the combination) was the agent supported by evidence
]. This had happened despite a strong
microbiological literature base that showed alcohols to be potent
antiseptics. The misinterpretation of trial outcomes was
carried over into prominent guidelines, led to a number
of prominent recommendations for CHG alone, and
created widespread but in parts unsubstantiated views of
CHG as an “in” antiseptic.
Microbiological assessment of antiseptics may
similarly be subject to errors. Both European and US
standards stipulate that adequately validated neutralizer
substances must be used at the point of sampling after
antiseptic exposure [
]; this is in order to prevent
continued killing due to residual bacteriostatic or
bactericidal action after the end of the dedicated exposure.
While this applies to the testing of all antiseptics, CHG
in particular is prone to false-positive efficacy
assessment in the absence of adequate neutralization, due to
strong bacteriostatic activity that it exerts at
concentrations far below bactericidal levels [
]. It has
been suggested that this is a factor that likely led to a
systematic skewing of the antiseptic literature [
Previous reports of superior performance of
CHGalcohol combination rubs for surgical hand antisepsis
] indeed attracted letters to the editor that
expressed concern about adequate neutralization [
In the present study, adequate neutralizers were used
during the entire testing process, thus creating equal sampling
conditions for both comparator rubs.
Among the different hand hygiene agents,
alcoholbased handrubs are generally most well tolerated on
skin; true alcohol allergies have not been documented
beyond reasonable doubt, and irritant contact
dermatitis from alcohols is rare when handrubs are well
formulated with emollients [
]. On the other hand,
CHG is a known allergen and a frequent cause of
irritant contact dermatitis among healthcare personnel
2, 36, 37
]. It has also been the subject of a recent US
FDA warning about rare but serious anaphylactic
]. Thus, there is a clear potential for a
tolerability advantage from alcohol-only handrubs for
surgical hand preparation, especially if their
antimicrobial performance characteristics are equal to or even
better than those of CHG-containing ones.
It is a limitation of our study that it was performed
according to a modified EN 12791 protocol, and
results from EN 12791 testing do not necessarily
translate into congruent results according to the US
standard ASTM E1115 [
], mainly due to the US
standard’s requirement for incremental increases
(cumulative effects) in log reduction factors on
subsequent days of testing [
]. However, the clinical
relevance of this requirement has been questioned,
because it is not intuitive why a surgeon’s hands after
antisepsis should be permitted to have different
microbial counts on different working days of the week .
In any case, EN 12791 is a very stringent standard in
which only very potent handrubs tend to pass, and it
has high inter-laboratory reproducibility [
In the present study, an alcohol-only handrub
containing a mix of ethanol and n-propanol outperformed a
CHG-alcohol handrub both immediately after
application and at 6 h when applied for 1.5 min and tested
according to a modified EN 12791 protocol in 25 healthy
volunteers. This means that optimized and
wellformulated alcohol-only handrubs can provide superior
performance to CHG-alcohol combination rubs for the
purpose of surgical hand preparation, even with
shortened application times, and this includes sustained
efficacy for an extended period of 6 h under surgical
gloves. In conclusion, given that CHG has a greater
potential for skin irritation than alcohols alone, CHG
is not an essential or even necessary component of
alcohol-based handrubs for surgical hand preparation.
Further studies in routine practice are warranted.
Availability of data and materials
The data that support the findings of this study are available from HygCen
but restrictions apply to the availability of these data, which were used
under license for the current study, and so are not publicly available. Data
are however available from the authors upon reasonable request and with
permission of HygCen.
SW, KN, AA modified the EN 12791 test method, analyzed and interpreted
the data regarding the efficacy. TH has born the idea for this investigation
and was a major contributor in writing the manuscript. All authors reviewed
and approved the final manuscript.
Ethics approval and consent to participate
Consent for publication
A. Arndt and T.-J. Hennig are paid employees of B. Braun Medical AG, the
manufacturer of the Softa-Man® alcohol-based handrub described in this
article. The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
1. Gröschel DHM , Pruett TL . Surgical antisepsis . In: Block SS, editor. Disinfection, sterilisation and preservation. 4th ed. London: Lea & Febiger; 1991 . p. 642 - 54 .
2. World Health Organization. WHO guidelines on hand hygiene in health care . Geneva: World Health Organization; 2009 .
3. Widmer AF . Surgical hand hygiene: scrub or rub? J Hosp Infect . 2013 ; 83 ( Suppl 1 ): S35 - 9 .
4. Graves PB , Twomey CL . Surgical hand antisepsis: an evidence-based review . Periop Nurs Clin . 2006 ; 1 : 235 - 49 .
5. Tanner J . Surgical hand antisepsis: the evidence . J Perioper Pract . 2008 ; 18 ( 8 ): 330 - 4 . 9
6. Boyce JM , Pittet D . 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. Society for Healthcare Epidemiology of America/Association for Professionals in infection control/Infectious Diseases Society of America . MMWR Recomm Rep . 2002 ; 51 (RR-16): 1 - 45 . quiz CE1-4
7. Association of perioperative Registered Nurses (AORN). Recommended practices for surgical hand antisepsis/hand scrubs . AORN J . 2004 ; 79 ( 2 ): 416 - 8 . 21 - 6 , 29 - 31
8. Hsieh HF , Chiu HH , Lee FP . Surgical hand scrubs in relation to microbial counts: systematic literature review . J Adv Nurs . 2006 ; 55 ( 1 ): 68 - 78 .
9. Graf ME , Machado A , Mensor LL , Zampieri D , Campos R , Faham L. Surgical hands antisepsis with alcohol-based preparations: cost-effectiveness, compliance of professionals and ecological benefits in the Brazilian healthcare scenario (in Portuguese) . J Bras Econ Saúde . 2014 ; 6 ( 2 ): 71 - 80 .
10. Parienti JJ , Thibon P , Heller R , et al. Hand-rubbing with an aqueous alcoholic solution vs traditional surgical hand-scrubbing and 30-day surgical site infection rates: a randomized equivalence study . JAMA . 2002 ; 288 ( 6 ): 722 - 7 .
11. Kampf G , Ostermeyer C , Heeg P. Surgical hand disinfection with a propanolbased hand rub: equivalence of shorter application times . J Hosp Infect . 2005 ; 59 ( 4 ): 304 - 10 .
12. European Committee for Standardization (CEN) . EN 12791 : 2016 . Chemical disinfectants and antiseptics. Surgical hand disinfection. Test method and requirement (phase 2/step2) . Brussels: European Committee for Standardization (CEN ); 2016 .
13. American Society for Testing and Materials (ASTM) . ASTM E1115-11 . Standard test method for evaluation of surgical hand scrub formulations West Conshohocken , PA: ASTM International; 2011 .
14. Food and Drug Administration_(FDA). Tentative final monograph for healthcare antiseptic drug products; proposed rule . 21 CFR parts 333 and 369. Fed Regist . 1994 ; 59 ( 116 ): 31402 - 52 .
15. Heeg P , Ostermeyer C , Kampf G. Comparative review of the test design tentative final monograph (TFM) and EN 12791 for surgical hand disinfectants . J Hosp Infect . 2008 ; 70 ( Suppl 1 ): 22 - 6 .
16. Beausoleil CM , Paulson DS , Bogert A , Lewis GS . In vivo evaluation of the persistant and residual antimicrobial properties of three hand-scrub and handrub regimes in a simulated surgical environment . J Hosp Infect . 2012 ; 81 ( 4 ): 283 - 7 .
17. Olson LK , Morse DJ , Duley C , Savell BK . Prospective, randomized in vivo comparison of a dual-active waterless antiseptic versus two alcohol-only waterless antiseptics for surgical hand antisepsis . Am J Infect Control . 2012 ; 40 ( 2 ): 155 - 9 .
18. Kampf G. “ Persistent activity”-should the effect of chlorhexidine in the sampling fluid and nutrient broth and on agar plates really be regarded as the effect on hands? Am J Infect Control . 2012 ; 40 ( 6 ): 579 .
19. Kampf G . How valid are the 'persistent and residual antimicrobial properties' described by Beausoleil et al .? J Hosp Infect . 2012 ; 82 ( 4 ): 301 - 2 .
20. European Committee for Standardization (CEN) . EN 13727 : 2012 +A2: 2015 . Chemical disinfectants and antiseptics. Quantitative suspension test for the evaluation of bactericidal activity in the medical area. Test method and requirements (phase 2, step 1). Brussels: European Committee for Standardization (CEN ); 2015 .
21. Kampf G , Ostermeyer C . Efficacy of two distinct ethanol-based hand rubs for surgical hand disinfection - a controlled trial according to prEN 12791 . BMC Infect Dis . 2005 ; 5 : 17 .
22. Rotter ML . Hand washing, hand disinfection, and skin disinfection . In: Wenzel RP, editor. Prevention and control of nosocomial infections. 3rd ed. Baltimore: Williams &Wilkins; 1997 . p. 691 - 709 .
23. Lilly HA , Lowbury EJ , Wilkins MD , Zaggy A . Delayed antimicrobial effects of skin disinfection by alcohol . J Hyg . 1979 ; 82 ( 3 ): 497 - 500 .
24. Ayliffe GA . Surgical scrub and skin disinfection . Infect Control . 1984 ; 5 ( 1 ): 23 - 7 .
25. Rotter ML , Kampf G , Suchomel M , Kundi M. Population kinetics of the skin flora on gloved hands following surgical hand disinfection with 3 propanolbased hand rubs: a prospective, randomized, double-blind trial . Infect Control Hosp Epidemiol . 2007 ; 28 ( 3 ): 346 - 50 .
26. Kampf G , Kramer A , Suchomel M. Lack of sustained efficacy for alcoholbased surgical hand rubs containing 'residual active ingredients' according to EN 12791 . J Hosp Infect . 2017 ; 95 ( 2 ): 163 - 8 .
27. Weber WP , Reck S , Neff U , et al. Surgical hand antisepsis with alcohol-based hand rub: comparison of effectiveness after 1.5 And 3 minutes of application . Infect Control Hosp Epidemiol . 2009 ; 30 ( 5 ): 420 - 6 .
28. Maiwald M. Technique is important for alcohol-based surgical hand antisepsis . Healthc Infect . 2012 ; 17 ( 3 ): 106 - 7 .
29. Burch TM , Stanger B , Mizuguchi KA , Zurakowski D , Reid SD . Is alcohol-based hand disinfection equivalent to surgical scrub before placing a central venous catheter? Anesth Analg . 2012 ; 114 ( 3 ): 622 - 5 .
30. Maiwald M , Chan ES . The forgotten role of alcohol: a systematic review and meta-analysis of the clinical efficacy and perceived role of chlorhexidine in skin antisepsis . PLoS One . 2012 ; 7 ( 9 ): e44277 .
31. Maiwald M , Chan ES . Pitfalls in evidence assessment: the case of chlorhexidine and alcohol in skin antisepsis . J Antimicrob Chemother . 2014 ; 69 ( 8 ): 2017 - 21 .
32. Kampf G , Shaffer M , Hunte C . Insufficient neutralization in testing a chlorhexidine-containing ethanol-based hand rub can result in a false positive efficacy assessment . BMC Infect Dis . 2005 ; 5 ( 1 ): 48 .
33. Kampf G . What is left to justify the use of chlorhexidine in hand hygiene? J Hosp Infect . 2008 ; 70 ( Suppl 1 ): 27 - 34 .
34. Kampf G , Reichel M , Hollingsworth A , Bashir M. Efficacy of surgical hand scrub products based on chlorhexidine is largely overestimated without neutralizing agents in the sampling fluid . Am J Infect Control . 2013 ; 41 ( 1 ): e1 - 5 .
35. Maiwald M , Petney TN , Assam PN , Chan ES . Use of statistics as another factor leading to an overestimation of chlorhexidine's role in skin antisepsis . Infect Control Hosp Epidemiol . 2013 ; 34 ( 8 ): 872 - 3 .
36. Kampf G , Kramer A . Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs . Clin Microbiol Rev . 2004 ; 17 ( 4 ): 863 - 93 . table of contents
37. Stingeni L , Lapomarda V , Lisi P . Occupational hand dermatitis in hospital environments . Contact Dermatitis . 1995 ; 33 ( 3 ): 172 - 6 .
38. US Food and Drug Administration (FDA). FDA Drug Safety Communication: FDA warns about rare but serious allergic reactions with the skin antiseptic chlorhexidine gluconate . 2017 . https://www.fda.gov/Drugs/DrugSafety/ ucm530975.htm. Accessed 12 Sept 2017 .
39. Kampf G , Ostermeyer C , Heeg P , Paulson D . Evaluation of two methods of determining the efficacies of two alcohol-based hand rubs for surgical hand antisepsis . Appl Environ Microbiol . 2006 ; 72 ( 6 ): 3856 - 61 .
40. Rotter M , Kundi M , Suchomel M , et al. Reproducibility and workability of the European test standard EN 12791 regarding the effectiveness of surgical hand antiseptics: a randomized, multicenter trial . Infect Control Hosp Epidemiol . 2006 ; 27 ( 9 ): 935 - 9 .