The sporicidal effects of a biodegradable peroxidic disinfectant

This study reports the results of an in vitro evaluation of the sporicidal and virucidal capacity of the new disinfectant Virkon. Suspensions of Bacillus subtilis strain pb 168 and Bacillus stearo-termophilus strain ATCC 10149 were used for this purpose. We exposed B. subtilis samples to the disinfectant diluted to 1% in both distilled water and in physiologic solution for varying lengths of time. The results, confirmed through a plating count of the surviving colonies and through observation with electronic microscopy of the preparations obtained, demonstrated that Virkon destroys spores within a few minutes of contact. Furthermore, the sporicidal effect on B. subtilis proved to be accelerated when the disinfectant is diluted in physiologic solution rather than in distilled water. The B. stearotermophilus spores were placed in contact with the disinfectant diluted to 1% and 2% concentrations in distilled water only. Again, optimal sporicidal effects were observed. The virucidal capacity of this disinfectant was tested on a pool of positive sera for viral hepatitis B (HBV). Preliminary observations with electronic microscopy showed the pool to contain a large quantity of complete and defective viral particles. The pool was then treated with specific anti-HBs im-mune globulins, placed in contact with the disinfectant and observed with electronic microscopy. Following contact with Virkon no complete viral particles were observed. Furthermore, it was no longer possible to demonstrate the immunological reactivity of HbsAg by means of ELISA testing.