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Objectives.To evaluate the reproducibility and workability of the in vivo test model of the European test standard EN 12791 regarding the effectiveness of surgical hand antiseptics and, as a secondary objective, to evaluate the power of the model to discriminate between the effectiveness of various formulations of surgical hand antiseptics.Design.Prospective, randomized, multicenter study with a Latin square design.Setting.Five laboratories at 2 universities, 2 disinfectant manufacturers, and 1 private testing institution.Participants.Twenty healthy adults in each laboratory.Intervention.Surgical hand antisepsis was performed by scrubbing with chlorhexidine gluconate 4% detergent (CHG) or by rubbing the hands with propan-2-OL (70% by volume; Iso 70) or ethanol 85% (E 85); rubbing the hands and forearms for 3 minutes with propan-1-OL (N 60) was used as the reference disinfection procedure. We deliberately chose to use these antiseptics at the given concentrations because they were intended to cover the range of typical antiseptics submitted for approval according to EN 12791.Methods.In once-weekly tests, the immediate effects of the 4 antiseptics were established according to the method laid down in EN 12791 by assessing the release of skin flora from the fingertips as viable bacteria counts per milliliter of sampling fluids before treatment and viable bacteria counts immediately after treatment, separately for both hands, such that after 4 weeks each volunteer had used every formulation once.Results.The mean log reduction factor (RF) for the release of bacterial skin flora (the log RF was calculated as the log count before treatment minus the log count after treatment) and corresponding standard deviations for the 4 hand antisepsis formulations were as follows: for CHG, 1.1 ± 0.3 colony-forming units (cfu) per milliliter of sampled fluid; for Iso 70, 1.7 ± 0.3 cfu/mL; for E 85, 2.1 ± 0.3 cfu/mL; and for N 60, 2.4 ± 0.4 cfu/mL. The differences between these values proved significant (PPP>.01). Relating the log RF values of the other 3 formulations to those of the reference formulation (N 60) abolished differences between laboratories (P = .16); in addition, the interclass correlation coefficient decreased from 9.1% to 4.5%. With 20 volunteers, a minimum difference of 0.47 log between the mean log RFs of the reference formulation and an inferior test formulation will be detected as significant at an α of .05 (1-sided) and a 1 — β value of .8.Conclusion.The test method described in EN 12791 yielded the same conclusion on the effectiveness of the tested formulations in every laboratory and proved, therefore, reproducible and workable.

Background Alcohol-based hand rubs (ABHR) range in alcohol concentration from 60-95% and are available in a variety of delivery formats, such as rinses, gels, and foams. Recent studies suggest that some ABHR foams dry too slowly, thereby encouraging the use of inadequate volumes. This study investigates the influence of product volume, delivery format, and alcohol concentration on dry-time and antimicrobial efficacy of ABHR foams, gels and rinses. Methods ABHR dry-times were measured using volunteers to determine the influences of product volume, delivery format, and alcohol concentration. ABHR efficacies were evaluated according to the European Standard for Hygienic Hand Disinfection (EN 1500) using 3-mL application volumes rubbed for 30 s, and additionally, using volumes of the products determined to rub dry in 30 s. Results Volumes of six ABHR determined to rub dry in 30 s ranged from 1.7 mL to 2.1 mL, and the rate of drying varied significantly between products. ABHR dry-times increased linearly with application volume and decreased linearly with increasing alcohol concentration, but were not significantly influenced by product format. An ABHR foam (70% EtOH), rinse (80% EtOH), and gel (90% EtOH) each met EN 1500 efficacy requirements when tested at a volume of 3 mL, but failed when tested at volumes that dried in 30 s. Conclusions Application volume is the primary driver of ABHR dry-time and efficacy, whereas delivery format does not significantly influence either. Although products with greater alcohol concentration dry more quickly, volumes required to meet EN 1500 can take longer than 30 s to dry, even when alcohol concentration is as high as 90%. Future studies are needed to better understand application volumes actually used by healthcare workers in practice, and to understand the clinical efficacy of ABHR at such volumes. Electronic supplementary material The online version of this article (doi:10.1186/1471-2334-14-511) contains supplementary material, which is available to authorized users.