Evaluation of virus removal efficiency with a microfiber cleaning cloth

Abstract

Toraysee for CE® (hereinafter, referred to as Toraysee) is a microfiber cloth with a fiber diameter of 2 μm developed by Toray specifically for the purpose of cleaning medical equipment and has been in use in clinical practice. Hie performance of the product is evaluated by the adenosine triphosphate (ATP) wipe test. We compared the virus removal efficiency of Toraysee with those of a cleaning cloth impregnated with quaternary ammonium salt (hereinafter, referred to as the Disinfectant cleaning cloth), which is commonly used in Japanese hospitals. Feline calicivirus F-9 (ATCC VR-782), a norovirus-related species, was used as the test viral strain. Viral infectivity was measured by a plaque assay using CRFK cells. Viral infectivity per 1 mL of the viral eluting solution was calculated from the number of CPEs caused by viral infection, dilution factor and inoculum dose, and the plaque-forming unit per test sample carrier (PFU/carrier) was calculated from the total volume of viral eluting solution (10 mL). The virus removal test was performed at the virus section of the Kitasato Research Center for Environmental Science. For this test no cleaning chemical was used and Toraysee was moistened only with water, but the test result indicates a high virus removal efficiency of 99.9%, demonstrating a superior performance over Disinfectant cleaning cloth. This result suggests that sufficient virus removal can be achieved only with mechanical wiping, without any disinfectant. Furthermore, Toraysee did not re-spread captured viruses over the surface. These observations indicate the potential of the product as a new means of viral infection control. While viral infection control is usually attempted by the use of antiviral drugs, the use of Toraysee may be beneficial in some circumstances where the presence of drug remnants may affect the patient, such as the cleaning of neonatal incubators.