The rapid detection of direct-acting DNA mutagens by electrical impedence with a DNA repair-deficient strain of Escherichia coli

A differential killing assay using Escherichia coli WP2 (wild type) and WP67 (uvrA, polA) was combined with impedence microbiology to produce a rapid screening method for direct-acting mutagenic compounds. The assay showed that mitomycin C, N-nitroso guanidine, potassium dichromate, sodium azide and acridine orange were direct-acting mutagens. With this method results can be obtained within hours, as compared with two days for the standard Salmonella/microsome test.