Assessment of chemical disinfectants against human immunodeficiency virus: Overcoming the problem of cytotoxicity and the evaluation of selected actives

Abstract The aim of this study was to develop a standardised technique for assessing the virucidal activity of commercial disinfectants against human immunodeficiency virus (HIV). In the absence of any model procedure for HIV a protocol based on German DVV guidelines was developed. A major difficulty associated with such studies is the cytotoxic effect of the biocide on the target cells used in infectivity assays. This problem is most commonly overcome by dilution of the virus-disinfectant mixture, however, this requires high titre (⩾ 10 7 TCID 50 ) virus which is difficult to achieve with HIV. We employed a simple washing technique which effectively removed cytotoxicity while retaining infectivity. Incorporated into a standard suspension test, this method supported by virus isolation procedures was sensitive and reproducible. The reliability of the procedure was confirmed by evaluating the efficacy of some commercially available cidals which were known to be cytotoxic; namely two instrument disinfectants, Sactimed-I-Steril, an aldehyde based product, Sactimed-I-Sinald a guanide/quaternary-ammonium combination, and Levermed, an alcohol based hand disinfectant.