Comparative assessment of the SOS Chromotest kit and the Mutatox test with the Salmonella plate incorporation (Ames test) and fluctuation tests for screening genotoxic agents

Abstract

Genuine needs for rapid, simple, and cost-efficient biotesting procedures to screen an ever-increasing number of chemicals and environmental samples are making the search for such assays a constant endeavor. With respect to genotoxicity screening, we compared, in this study, the performance of two novel assays (Vibrio fischeri M169 Mutatox™ assay and the Escherichia coli PQ37 SOS Chromotest kit assay) with two well-established Ames testing procedures (plate incorporation and fluctuation assays). Testing material included 14 chemicals (10 potentially directly acting and 4 indirectly acting compounds) reflecting different chemical classes (2 inorganics, 2 pesticides, 2 halogenated hydrocarbons, 2 alkylating agents, 2 aromatic amines, 1 chlorophenol, and 3 polycyclic aromatic hydrocarbons). Comparative assessment criteria included (1) interprocedural agreement in detecting presence or absence of genotoxicity, (2) accuracy in being able to recognize animal (non)carcinogens, and (3) sensitivity (detection of lowest actively genotoxic concentration). In terms of qualitative responses, both the SOS Chromotest (86% agreement) and Mutatox assays (93% agreement) were good predictors of the Ames testing mutagenicity. For their capability to correctly discriminate between (non)carcinogens, accuracy was 82% (9 of 11 chemicals) for Mutatox, 73% (8 of 11 chemicals) for Ames testing, and 64% (7 of 11 chemicals) for the SOS Chromotest. In general, the Salmonella-based assays proved more sensitive (6 times out of 9 chemicals) than the Mutatox (3 times out of 9 chemicals) and the SOS Chromotest (never more sensitive). Overall, this study demonstrates reliable performances by both the SOS Chromotest and Mutatox for chemical genotoxicity screening when results are referenced to the well-validated Ames assay. Although additional comparative data with other chemicals will be required, it appears likely that these more practical and cost-efficient procedures can be presently useful to screen genotoxic activity of various xenobiotics and environmental samples. © 1994 by John Wiley & Sons, Inc..