Epidemiology and Infection

Special Article

Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses

S. A. Sattara1, V. S. Springthorpea1, Y. Karima1 and P. Loroa1

a1 Department of Microbiology and Immunology, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5

Abstract

The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenzavirus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 µl amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were selected for this study based on the findings of an earlier investigation with a human rotavirus.After 1 min exposure to 20 µl of the disinfectant, the virus from the disks was immediately eluted into tryptose phosphate broth and plaque assayed. Using an efficacy criterion of a 3 log10 or greater reduction in virus infectivity titre and irrespective of the virus suspending medium, only the following five disinfectants proved to be effective against all the four viruses tested: (1) 2% glutaraldehyde normally used as an instrument soak. (2) a strongly alkaline mixture of 0·5% sodium o-benzyl-p-chlorophenate and 0·6% sodium lauryl sulphate, generally used as a domestic disinfectant cleaner for hard surfaces, (3) a 0·04% solution of a quaternary ammonium compound containing 7% hydrochloric acid, which is the basis of many toilet bowl cleaners. (4) chloraminc T at a minimum free chlorine level of 3000 p.p.m. and (5) sodium hypochlorite at a minimum free chlorine concentration of 5000 p.p.m. Of those chemicals suitable for use as topical antiseptics, 70% ethanol alone or products containing at least 70% ethanol were ineffective only against coxsackievirus B3. These results emphasize the care needed in selecting chemical disinfectants for routine use in infection control.

(Accepted January 27 1989)

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