Mutants of the luminescent bacterial strain NRRL B-11177 were isolated with pleiotropic hypersensitivity towards hydrophobic antimicrobial agents. SDS-PAGE analyses of outer membrane proteins and lipopolysaccharides revealed that the outer membrane structure of the ahs-mutants was altered. QSAR analysis showed that the inhibitory effect of chloro-substituted phenols on bioluminescence of the ahs-mutants depended on their hydrophobicity. The effect of chlorinated phenols and detergents on bioluminescence was increased in the ahs-mutants. The potential use of these mutants in bioluminescent toxicity tests was discussed.