RESISTANCE AND CROSS RESISTANCE OF ESCHERICHIA COLI S MUTANTS TO THE RADIOMIMETIC AGENT NITROFURAZONE.

Woody-Karrer, Pearl (Palo Alto Medical Research Foundation, Palo Alto, Calif.) and Joseph Greenberg. Resistance and cross resistance of Escherichia coli S mutants to the radiomimetic agent nitrofurazone. J. Bacteriol. 85:1208-1216. 1963.-Cross-resistance relationships are described for 73 mutants of Escherichia coli strain S selected in one step for resistance to nitrofurazone. The test agents included ultraviolet radiation, five radiomimetic compounds, and penicillin; 12 different types of mutants could be selected. Two of these were chemoresistant, three were identical to radioresistant types previously isolated by use of other radiomimetic agents, and seven represented previously unobserved radioresistant types. The majority of radioresistant strains did not respond to plating-medium reactivation after ultraviolet radiation, despite the ultraviolet radiation responses of several minority representative strains. The data presented indicate that radioresistance in E. coli S does not involve resistance to most toxic agents; on the other hand, cross resistance to radiomimetic compounds is not restricted to alkylating agents.