Efficacy of EPA-registered disinfectants against two human norovirus surrogates and Clostridioides difficile endospores.

Abstract

To determine the efficacy of a panel of nine EPA-registered disinfectants against two human norovirus (HuNoV) surrogates (feline calicivirus [FCV] and Tulane virus [TuV]) and Clostridioides difficile endospores. Nine EPA-registered products, five of which contained H2 O2 as active ingredient, were tested against infectious FCV, TuV and C. difficile endospores using two ASTM methods, a suspension and carrier test. Efficacy claims against FCV were confirmed for 8 of 9 products. The most efficacious product containing H2 O2 as ingredient achieved a>5.1 log reduction of FCV and>3.1 log reduction of TuV after 5min, and >6.0 log reduction of C. difficile endospores after 10min. Of the five products containing H2 O2 , no strong correlation (R2 =0.25, p=0.03) was observed between disinfection efficacy and H2 O2 concentration. Addition of 0.025% ferrous sulphate to 1% H2 O2 solution improved efficacy against FCV, TuV and C. difficile. Disinfectants containing H2 O2 are the most efficacious disinfection products against FCV, TuV and C. difficile endospores. Product formulation, rather than the concentration of H2 O2 in a product, impacts the efficacy of a disinfection product. H2 O2 -based disinfectants are efficacious against surrogate viruses for HuNoV and C. difficile endospores.