Two methods of surgical hand antisepsis are commonly used: the hand scrub-brush method with antimicrobial soap and the hand-rub method with an alcohol solution. Very few clinical trials have been performed to compare the microbiological efficacy of these procedures in practical situations.Reference Bryce, Spence and Roberts1 The traditional surgical scrub method is usually performed with a designated brush and antimicrobial solutions containing chlorhexidine gluconate or povidone-iodine,Reference Widmer2 despite the fact that the World Health Organization (WHO) discourages the use of brushes as part of the surgical hand antisepsis because of the injuries caused to the skin by their abrasive effect.Reference Pittet, Allegranzi and Boyce3 Among the advantages of hand rub is its shorter hand antisepsis time,Reference Voss and Widmer4 easy application, and better compliance and tolerance among surgeons.Reference Girard, Amazian and Fabry5
The European standard EN 12791:2016+A1:2018 (UNE) establishes that the noninferiority requirements should fulfill the antiseptics intended for surgical hand disinfection versus to a specific reference product.Reference European Norm6 The UNE proposes propan-1-ol 60% (P-1) as a reference product to determine the bactericidal efficacy by rubbing it, and the recommendation provided by the antiseptic manufacturers is usually for the use of a scrub brush.
Here, we compare the bactericidal efficacy of the reference antiseptic product P-1 using hand rub and hand scrub-brush methods. We test whether P-1 with a scrub brush is suitable for hand disinfection according to the UNE standard.
Methods
A crossover trial was performed from September 2019 to January 2020 at Complutense University of Madrid, Spain. The Ethics Committee for Clinical research of the Hospital Universitario Clínico San Carlos, Madrid, approved the trial (ID: 16/122-E TFM), and the trial was registered at ClinicalTrials.gov (ID: NCT04446923). All participants provided written informed consent. In total, 24 participants were randomly divided into 2 groups of 12 participants in the first run. Group 1 used the reference surgical hand rub with P-1,Reference European Norm6 and group 2 used the hand scrub-brush method with P-1.Reference European Norm6 After at least 1 week to allow reconstitution of normal skin flora,Reference European Norm6 the test was repeated with the roles changed in a second run. At the end of the 2 experiments, each participant had performed each antisepsis procedure once.
To remove transient bacterial flora foreign agents, the participant’s hands were washed with a diluted soft soap. They were then rinsed under running water and dried with a towel. To assess the release of the skin microorganisms prior to surgical hand antisepsis (prevalues), immediately after drying, participants rubbed all 10 fingertips for 1 minute on the base of 2 petri dishes, 1 for each hand, each containing 10 mL tryptone soy broth (Becton Dickinson, Franklin Lakes, NJ) as the sampling fluid. The dishes were incubated for 20–24 h at 37 ± 1°C, and the colony-forming units (CFU/mL) values were calculated.
For the hand-rub method, 3 mL of P-1 was poured into cupped dried hands of participants and rubbed vigorously to ensure total coverage of the hands. Because P-1 evaporates, to keep the hands wet for the full 3-minute contact time, when almost dry, additional aliquots of 3 mL of P-1 were applied.
For the scrub-brush method, fingernails were scrubbed with a sterile brush, and hands and forearms were washed over a period of 3 minutes.
As soon as the participant’s hands were dry after antiseptic application, we used the same bacterial sampling procedure as after the preparatory hand wash described above, but for the right hand only (immediate postvalue). Immediately thereafter, both hands were protected from contamination by donning sterile surgical gloves (without powder) to be removed after 3 hours. The gloves were then removed, and the bacterial sampling was repeated, this time for the left hand (3-hour postvalue).Reference European Norm6 Immediate and 3-hour reduction effects were determined using “prevalues minus postvalues” (CFU/mL) for the right or the left hand, respectively.
Statistical analysis
The Wilcoxon signed ranges test was used to compare the results obtained in the same washing procedure at the beginning and after the surgical hand antisepsis. The Mann-Whitney U test was used to compare the efficacies of the scrubbing and rubbing techniques. Statistical significance was set at P < .05 with a 95% confidence interval.
Results
As showed in Table 1, hand rub and scrub-brush methods using P-1 significantly reduced CFU/mL of bacteria on the right hands when measured immediately after washing. There was a significant reduction in prevalues immediately after washing [from 3.52 ± 0.84 CFU/mL to 1.81 ± 0.97 CFU/mL (P < .001)] and with the scrub-brush method [from 3.91 ± 0.86 CFU/mL to 3.07 ± 0.96 CFU/mL (P < .001)].
Table 1. Logarithmic Values of the Total Counts of Colony-Forming Units (CFU/mL) and the Logarithm of the Immediate Reduction (lg R immediate) According to the UNE Standard Using the 2 Methods of Surgical Hand Antisepsis: Hand Scrub Brush Using the P-1 for 1 minute and the P-1 Hand Rub Control Method
Note. Scrub, antisepsis method using the P-1 hand scrub-brush method with a sponge bristle brush for 1 minute; Rub, antisepsis method of control using hand rub according to UNE; CFU/mL, colony-forming units; SD, standard deviation; CI, confidence interval; IQR, interquartile range; Lg R immediate, logarithm reduction immediate effect expressed by decimal logarithms of “log prevalue minus log postvalue.”
a Wilcoxon nonparametric test for related samples. Statistical significance at P < .05, with a 95% confidence interval.
Regarding the sustained effect donning surgical gloves 3 h after surgical antisepsis, the hand rub method significantly reduced CFU/mL at 3 hours on the left hands from 3.52 ± 0.88 CFU/mL to 2.00 ± 0.90 CFU/mL (P < .001). When using the scrub brush, there was no significant reduction from 3.94 ± 0.70 CFU/mL to 3.50 ± 0.99 CFU/mL (P = .094) (Table 2).
Table 2. Logarithmic Values of the Total Counts of Colony-Forming Units (CFU/mL) and Logarithm Reduction 3-Hour Effect (Lg R 3 Hours) According to the UNE Standard Using the 2 Methods of Surgical Manual Antisepsis: Hand Scrub Brush With the P-1 for 1 Minute and the P-1 Hand Rub Control Method
Note. Antisepsis method: Scrub, using the P-1 hand scrub-brush method with a sponge bristle brush for 1 mine; Rub, by the method of control using hand rub according to UNE; CFU/mL, colony-forming units; SD, standard deviation; CI, confidence interval; IQR, interquartile range; Lg R 3 hours, logarithm reduction at 3-hour effect expressed by decimal logarithms of “log prevalue minus log 3-hour postvalue.”
a Wilcoxon nonparametric test for related samples. Statistical significance at P < .05, with a 95% confidence interval.
The immediate reduction effects of CFU/mL at the right hand is significantly greater with the hand rub method, with a value of 1.69 ± 0.95 CFU/mL compared with the scrub brush method with a reduction of only 0.84 ± 0.59 CFU/mL (P = .004). Also, the 3 h reduction effects of CFU/mL in left hands have been significantly higher using the hand rub method, with a value of 1.52 ± 1.08 CFU/mL compared with a reduction of only 0.44 ± 1.05 CFU/mL using the hand scrub-brush method (P = .004).
Discussion
In our crossover trial, we observed that the efficacy of P-1 in surgical hand antisepsis is highly dependent on the antiseptic application procedure (hand rub vs scrub brush). Our results suggest that the scrubbing method should be replaced by the rubbing method because the bacterial recolonization of the skin of the individual after the application of antiseptics is strongly linked to the form of administration. When rubbing the antiseptic, recolonization slows significantly compared to the scrub brush method.
The evaluation of studies of reduction of bacterial load on the skin of the hands has a number of limitations; because of the great variability among study methods used without complying with standardized norms, it is difficult or even impossible to compare the results obtained in other studies.Reference da Cunha, Matos, da Silva, de Araújo, Ferreira and Graziano7,Reference Rosenthal, Bijie and Maki8
In conclusion, even using the same product (P-1), the mean reduction for the immediate effect of using a hand scrub brush was inferior to that achieved by hand rub. Also, the hand scrub brush with P-1 did not demonstrate a sustained effect; the mean reduction for the 3-hour effect was not superior to that achieved by the same P-1 by hand rub. Therefore, the manufacturers of antiseptic products should test which method is superior to that achieved by the reference product P-1, according to the UNE, before recommending the use of a scrub brush instead of hand rub.
Acknowledgments
Financial support
No financial support was provided relevant to this article.
Conflicts of interest
All authors report no conflicts of interest relevant to this article.
