ASSESSMENT OF CHEMICAL DISINFECTANTS AGAINST HUMAN-IMMUNODEFICIENCY-VIRUS - OVERCOMING THE PROBLEM OF CYTOTOXICITY AND THE EVALUATION OF SELECTED ACTIVES

The aim of this study was to develop a standardised technique for asse ssing the virucidal activity of commercial disinfectants against human immunodeficiency virus (HIV). In the absence of any model procedure f or HIV a protocol based on German DVV guidelines was developed. A majo r difficulty associated with such studies is the cytotoxic effect of t he biocide on the target cells used in infectivity assays. This proble m is most commonly overcome by dilution of the virus-disinfectant mixt ure, however, this requires high titre (greater than or equal to 10(7) TCID50) virus which is difficult to achieve with HIV. We employed a s imple washing technique which effectively removed cytotoxicity while r etaining infectivity. Incorporated into a standard suspension test, th is method supported by virus isolation procedures was sensitive and re producible. The reliability of the procedure was confirmed by evaluati ng the efficacy of some commercially available cidals which were known to be cytotoxic; namely two instrument disinfectants, Sactimed-I-Ster il, an aldehyde based product, Sactimed-I-Sinald a guanide/quaternary- ammonium combination, and Levermed, an alcohol based hand disinfectant .