Of Bacteria and Men: Toxicity of 30 MEIC Chemicals to Bacteria and Humans

The toxicity of chemicals (numbers 11–30 from the multicenter evaluation of in vitro cytotoxicity [MEIC] programme) to Escherichia coli and Bacillus subtilis was examined. Malathion was not detectably toxic to bacteria. Theophylline was toxic to E. coli but not to B. subtilis. All of the other chemicals were toxic to both bacteria, with minimal inhibitory concentrations (MIC) ranging from 10^-5M to 1.3M. The sensitivities of both organisms to the chemicals were quite similar. A highly significant correlation could be established for the first 30 MEIC chemicals between MIC in bacteria and acute lethal blood concentration in humans. A significant correlation was also established for sets of MEIC chemicals between MIC in bacteria and the relevant endpoint concentrations in various tests employing human cells.