Purpose: This study determined the effect of 0.32 mg/ml benzalkonium chloride (BAC), 5 mg/ml potassium peroxymonosulfate (KPMS), and a commercial cleanser (ADBAC; recommended concentration of 1:128 dilution) over 1 h at room temperature against human norovirus (hNoV) surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1) in vitro.
Methods: FCV-F9 and MNV-1 at titers of ~4 log PFU/ml were treated with equal volumes of three chemicals or water (control) at room temperature for 0, 5, 10, 15, 30, and 60 min. Treatments were neutralized and serial dilutions of treated and untreated viruses were plaque assayed. All treatments were replicated thrice and assayed in duplicate.
Results: Treatment of FCV-F9 with BAC for 5, 10, and 15 min resulted in <1 log PFU/ml reduction, with ~1 log PFU/ml reduction after 30 min, and ~2.8 log PFU/ml after 1 h. FCV-F9 showed no significant titer reduction with ADBAC for 5, 10, 15, or 30 min, with only ~1 log PFU/ml reduction after 1 h. No obvious MNV-1 reduction was obtained after treatment with BAC or ADBAC for 5 or 10 min, but MNV-1 was found to be reduced by ~3 log PFU/ml (based on countable plaques/assay detection limit) after 1 h with BAC, and ~1 log PFU/ml reduction was obtained with ADBAC for 15 min. FCV-F9 and MNV-1 at low titers were reduced to undetectable levels by KPMS for all tested times.
Significance: Our results indicate that KPMS appears to be the most suitable of the three tested chemicals for hNoV surrogate reduction, with broad-spectrum application for clinical and industrial settings.