Evaluation of the virucidal efficacy of disinfectant wipes with a test method simulating practical conditions

Abstract

Background The use of disinfectant wipes in hospitals is increasing over the last years. These wipes should be able to inactivate microorganisms including viruses on environmental surfaces and to prevent their transfer to clean areas. The European norm (EN) 16615:2015 describes a wiping process over four fields starting on the contaminated field 1 followed by fields 2–4 and back to the starting point (4-field test). This test method exclusively describes killing and transfer of vegetative bacteria and fungi by disinfectant wipes without measuring virucidal activities. Therefore, it was the aim of this study to use the existing test methodology additionally to evaluate virus inactivation by wipes. Methods The 4-field test was performed with four commercially available disinfectant wipes including the examination of the active solutions of these wipes with a reference wipe. Murine norovirus (MNV) as surrogate of human noroviruses, adenovirus (AdV) type 5 and polyomavirus SV40 (SV40) were chosen as test viruses. Results The per acetic acid (PAA)-based wipe (wipe A) was able to inactivate all three test viruses resulting in a four log 10 reduction on test field 1, whereas the quaternary ammonium compound (QAC)-based products (wipes B and C) failed to reach such reduction. Both QAC-based wipes were able to inactivate SV40 and only the active solution of wipe B was effective against MNV. Another wipe with 2-propanol as active ingredient (wipe D) was not able to show a sufficient efficacy against all three test viruses. There was a good agreement between the results of the wipes and the corresponding fluids showing no influence of the material of wipes. Tests with the 2-propanol-based wipe D showed a transfer of all test viruses to the non-contaminated test fields 2–4. SV40 was additionally transferred by the QAC-based wipe C with 0.78% active ingredients to these additional fields. In all other cases no virus transfer to test fields 2–4 was observed. Finally, no virus could be detected in the PAA-based wipe A after usage in the 4-field test in contrast to the other wipes examined. Conclusions The successful performance of a 4-field test with viruses demonstrated that the existing wiping method with bacteria and fungi can be used in addition for measuring virucidal efficacy. The virus-inactivating properties of surface disinfectants could be evaluated therefore with a test simulating practical conditions with mechanical action resulting in more reliable data than the existing quantitative suspension tests and/or a carrier test without any mechanical action.

Disinfectant Wipes with Nonsporicidal Claims Transfer Clostridioides difficile Spores from Contaminated Surfaces to Uncontaminated Surfaces during the Disinfection Process

“…However, overall, there were no significant differences in the log 10 CFU/100 cm 2 of spores transferred to the 0.5 m 2 1.0 m 2 , 1.5 m 2 and 2.0 m 2 surface areas. In a similar study, Becker et al did not find significant differences in the titer of viruses detected from three 25 cm 2 uncontaminated surfaces after wiping them with a QAC disinfectant wipe previously used on a contaminated surface [26]. The reported risk of cross-contamination by C. difficile spores is particularly relevant in healthcare settings as C. difficile infections have been associated with contaminated environmental surfaces [30,31,32].…”

“…Cross-contamination is described by the CDC as the transfer of bacteria by contact from one surface to another [28]. Disinfectant wipes were the transfer "agents" between the surface inoculated with C. surface onto three other surfaces of the same size in the process of using the wipes [26].…”

“…The risk of pathogen transmission by the hands of healthcare workers and patients has been widely investigated [23,24,25]. However, less work [17,26] has been done to determine the risk of crosscontamination by disinfectant wipes using real world techniques in vitro. The objective of this study was to determine the cross-contamination risk that disinfectant towelettes with no sporicidal claims may pose when challenged with C. difficile spores.…”

Synergistic effects of anionic surfactants on coronavirus (SARS-CoV-2) virucidal efficiency of sanitizing fluids to fight COVID-19

“…Swabs of each field were transferred to 5 ml Minimum Essential Medium (MEM), respectively, and tubes were vortexed for 120 s. Virus titres were determined by endpoint dilution techniques according to the EN 14476:2015 European Standard and calculated using the method of Kärber and Spearman [12,13]. The virus reduction factor (RF) on the test fields was then determined according to the method described in details by Becker et al [14]. All experiments were carried out in triplicates.…”

Disinfectant Wipes Transfer Clostridioides difficile Spores from Contaminated Surfaces to Uncontaminated Surfaces during the Disinfection Process

“…The risk of pathogen transmission by the hands of healthcare workers and patients has been widely investigated [24,25,26]. However, less work [17,27] has been done to determine the risk of crosscontamination by disinfectant wipes using real world techniques in vitro as standard testing for the registration of towelette products rarely mandate the simulation of real world wiping scenarios [3].The objective of this study was to determine the cross-contamination risk that disinfectant towelettes with no sporicidal claims may pose when challenged with C. di cile spores. We hypothesized that although the tested disinfectant wipes have no sporicidal claims, they will reduce C. di cile spore loads, but crosscontamination may still occur.…”