Dry-Fog-Dekontamination von mikrobiologischen Sicherheitswerkbänken nach Tätigkeiten mit SARS-CoV-2: Zyklusentwicklung und Prozessvalidierung für die Trockenvernebelung von Peroxyessigsäure

Background: Technical protection measures for laboratory activities involving biological agents include biological safety cabinets (BSC) that may be contaminated. In the case of diagnostic activities with SARS-CoV-2, this may also affect BSC that are operated at protection level 2; therefore, decontamination of all contaminated surfaces of the BSC may be required. In addition to fumigation with hydrogen peroxide (HO), dry fogging of HO-stabilized peroxyacetic acid (PAA) represents another alternative to fumigation with formalin. However, to prove their efficacy, these alternatives need to be validated for each model of BSC.Methods: The validation study was performed on 4 different BSCs of Class II A2 using the “Mini Dry Fog” system.Results: An aerosol concentration of 0.03% PAA and 0.15% HO during a 30 min exposure was sufficient to inactivate SARS-CoV-2. Effective concentrations of 1.0% PAA and 5% HO were required to decontaminate the custom-prepared biological indicators loaded with spores of and deployed at 9 different positions in the BSC. Commercial spore carriers were easier to inactivate by a factor of 4, which corresponded to a reduction of 10 in all localizations.Conclusions: Dry fogging with PAA is an inexpensive, robust, and highly effective decontamination method for BSCs for enveloped viruses such as SARS-CoV-2. The good material compatibility, lack of a requirement for neutralization, low pH – which increases the range of efficacy compared to HO fumigation – the significantly shorter processing time, and the lower costs argue in favor of this method.