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Surface disinfectants are part of broader preventive strategies preventing the transmission of bacteria, fungi and viruses in medical institutions. To evaluate their virucidal efficacy, these products must be tested with appropriate model viruses with different physico-chemical properties under conditions representing practical application in hospitals.
The aim of this study was to evaluate a quantitative carrier assay. Furthermore, different putative model viruses like adenovirus type 5 (AdV-5) and different animal parvoviruses were evaluated with respect to their tenacity and practicability in laboratory handling. To evaluate the robustness of the method, some of the viruses were tested in parallel in different laboratories in a multi-center study. Different biocides, which are common active ingredients of surface disinfectants, were used in the test. After drying on stainless steel discs as the carrier, model viruses were exposed to different concentrations of three alcohols, peracetic acid (PAA) or glutaraldehyde (GDA), with a fixed exposure time of 5 minutes. Residual virus was determined after treatment by endpoint titration.
All parvoviruses exhibited a similar stability with respect to GDA, while AdV-5 was more susceptible. For PAA, the porcine parvovirus was more sensitive than the other parvoviruses, and again, AdV-5 presented a higher susceptibility than the parvoviruses. All parvoviruses were resistant to alcohols, while AdV-5 was only stable when treated with 2-propanol. The analysis of the results of the multi-center study showed a high reproducibility of this test system.
In conclusion, two viruses with different physico-chemical properties can be recommended as appropriate model viruses for the evaluation of the virucidal efficacy of surface disinfectants: AdV-5, which has a high clinical impact, and murine parvovirus (MVM) with the highest practicability among the parvoviruses tested.
Background: Vaccinia virus strain Lister Elstree (VACV) is a test virus in the DVV/RKI guidelines as representative of the stable enveloped viruses. Since the potential risk of laboratory-acquired infections with VACV persists and since the adverse effects of vaccination with VACV are described, the replacement of VACV by the modified vaccinia Ankara strain (MVA) was studied by testing the activity of different chemical biocides in three German laboratories. Methods: The inactivating properties of different chemical biocides (peracetic acid, aldehydes and alcohols) were tested in a quantitative suspension test according to the DVV/RKI guideline. All tests were performed with a protein load of 10% fetal calf serum with both viruses in parallel using different concentrations and contact times. Residual virus was determined by endpoint dilution method. Results: The chemical biocides exhibited similar virucidal activity against VACV and MVA. In three cases intra-laboratory differences were determined between VACV and MVA - 40% (v/v) ethanol and 30% (v/v) isopropanol are more active against MVA, whereas MVA seems more stable than VACV when testing with 0.05% glutardialdehyde. Test accuracy across the three participating laboratories was high. Remarkably inter-laboratory differences in the reduction factor were only observed in two cases. Conclusions: Our data provide valuable information for the replacement of VACV by MVA for testing chemical biocides and disinfectants. Because MVA does not replicate in humans this would eliminate the potential risk of inadvertent inoculation with vaccinia virus and disease in non-vaccinated laboratory workers.
Background A procedure for including activity against enveloped viruses in the post-contamination treatment of hands has been recommended, but so far no European standard is available to implement it. In 2004, the German Robert Koch-Institute (RKI) and the German Association for the Control of Virus Disease (DVV) suggested that vaccinia virus and bovine viral diarrhea virus (BVDV) should be used as test viruses in a quantitative suspension test to determine the activity of a disinfectant against all enveloped viruses. Methods We have studied the activities of three commonly-used alcohol-based hand rubs (hand rub A, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate; hand rub B, based on 80% ethanol; hand rub C, based on 95% ethanol) against vaccinia virus and BVDV, and in addition against four other clinically relevant enveloped viruses: herpes simplex virus (HSV) types 1 and 2, and human and avian influenza A virus. The hand rubs were challenged with different organic loads at exposure time of 15, 30 and 60 s. According to the guidelines of both BGA/RKI and DVV, and EN 14476:2005, the reduction of infectivity of each test virus was measured on appropriate cell lines using a quantitative suspension test. Results All three alcohol-based hand rubs reduced the infectivity of vaccinia virus and BVDV by >= 4 log10-steps within 15 s, irrespective of the type of organic load. Similar reductions of infectivity were seen against the other four enveloped viruses within 15 s in the presence of different types of organic load. Conclusions Commonly used alcohol-based hand rubs with a total alcohol concentration >= 75% can be assumed to be active against clinically relevant enveloped viruses if they effectively reduce the infectivities of vaccinia virus and BVDV in a quantitative suspension test.