Bactericidal Activity of Ready-To-Use Alcohol-Based Commercial Wipes According to EN 16615 Carrier Standard

Abstract

Background: The effectiveness of ready-to-use disinfectant wipes was previously assessed in standardized suspension tests, which were inadequate because they ignored that the wipes are rubbed against a surface. Thus, we assessed the effectiveness of commercially available disinfectant wipes impregnated with an alcoholic solution according to the 16615 standard, which includes a test with mechanical action. Methods: According to the EN 16615 standard, under clean conditions, four squares (5cm x 5 cm), placed next to one another, were marked on a test surface. Enterococcus hirae, Pseudomonas aeruginosa, and Staphylococcus aureus were inoculated on the leftmost square, and a wipe impregnated with an alcoholic solution was placed to the left of that square. Then, the wipe was pressed with a 2.5 kg weight and moved to the right and back to the left. After contact times of 1, 5, 10, or 15 minutes, we measured the reduction in bacterial load. Results: Alcohol-based ready-to-use commercial wipes did not show sufficient bactericidal activity at the contact times of 1, 5, 10 and 15 minutes. Wipes containing propan-1-ol and a mixture of propan-1-ol and propan-2-ol were active against Pseudomonas aeruginosa at the contact times of 1 minute and 15 minutes. None of the examined wipes were active against Enterococcus hirae or Staphylococcus aureus. Conclusion: Bactericidal parameters of ready-to-use disinfectant wipes should be determined in surface tests, in addition to suspension tests, because suspension tests do not simulate the conditions under which disinfectant wipes are used in practice.

Application of EN 16615 (4-Field Test) for the Evaluation of the Antimicrobial Activity of the Selected Commercial and Self-Made Disinfectant Wipes

“…In the conducted research, wipes soaked in ethanol (self-made wipes) had bactericidal activity in contrast to commercial wipes with ethanol. The lack of sufficient bactericidal activity was also demonstrated in the studies by Andersen et al [17] and Tarka et al [18]. No differences in the degree of microbial reduction were observed for the commercial wipes and for the wipes soaked in propanol.…”

Contact time has limited impact on the efficacy of disinfectant towelettes when tested under conditions reflective of realistic use

“…Only QAC3 was able to achieve an average 5-log reduction under the testing conditions used in this study; even then, this was only achieved against P. aeruginosa, not S. aureus. This discrepancy in performance under the novel testing conditions is not surprising, as this has been seen previously in the literature when testing commercial disinfectant towelette products under conditions more re ective of realistic use [23,31]. Further, others [32] have found that the method used to test disinfectant e cacy results in signi cant differences in performance.…”

“…While other studies have examined the impact of contact time on the e cacy of disinfectant towelettes [21][22], few have studied this variable under conditions re ective of realistic use. Tarka et al, (2019) [23] examined the e cacy of several disinfectant towelette products across a range of contact times; however, the products studied all had contact times of one min or less, and the contact times examined were at or beyond the label contact time for all products studied. The objective of this study was to determine the e cacy of disinfectant towelette products when applied for a practical, relevant contact time of one min compared to contact times of both shorter and longer duration, and when done so under conditions designed to re ect realistic use.…”

Contact time has limited impact on the efficacy of disinfectant towelettes when tested under conditions reflective of realistic use

“…Only QAC3 was able to achieve an average 5-log reduction under the testing conditions used in this study; even then, this was only achieved against P. aeruginosa , not S. aureus. This discrepancy in performance under the novel testing conditions is not surprising, as this has been seen previously in the literature when testing commercial disinfectant towelette products under conditions more reflective of realistic use [ 23 , 31 ]. Further, others [ 32 ] have found that the method used to test disinfectant efficacy results in significant differences in performance.…”

“…While other studies have examined the impact of contact time on the efficacy of disinfectant towelettes [ 21 , 22 ], few have studied this variable under conditions reflective of realistic use. Tarka et al, (2019) [ 23 ] examined the efficacy of several disinfectant towelette products across a range of contact times; however, the products studied all had contact times of one min or less, and the contact times examined were at or beyond the label contact time for all products studied.…”