Mutants resistant to nalidixic acid and novobiocin. specific features of formation from E. Coli strains with RecA or LexA mutations
The main problem of modern medical microbiology is the widespread resistance of bacteria to many antibiotics used in therapy. A resistant phenotype is mainly formed due to mutations in the bacterial genome. One of the proposed mechanisms for the occurrence of mutations is the impact of an inducible SOS-response system, whose proteins are synthesized in bacteria under the antibiotic pressure. The proteins RecA and LexA, encoded by the corresponding genes were shown to be the regulators of the SOS response in bacteria. We have studied the effect of recA13 and lexA1 mutations on the resistance of bacteria to nalidixic acid and novobiocin, as well as their effect on the rate of antibiotic resistance mutations. We have shown that the SOS-response system plays a minor role in formation of bacterial resistance to quinolones and aminocoumarins, and also in mutagenesis under the conditions of antibiotics pressure.