Characteristics of Emergence of Mutants Resistant to Nalidixic Acid and Novobiocin in E. coli Strains with recA and lexA Mutations

Resumo

The main problem of the modern medical microbiology is the widespread resistance of bacteria to many antibiotics used in therapy. Resistance to antibiotics is mainly developed due to mutations in the bacterial genome. One of the proposed mechanisms for the occurrence of mutations is the functioning of the inducible SOS response system, the proteins of which are synthesized in the cell affected by antibiotics. The RecA and LexA proteins encoded by the corresponding genes are regulators of the SOS response in bacteria. The effect of the recA13 and lexA1 mutations on bacterial resistance to nalidixic acid and novobiocin and on the rates of antibiotic resistance development was studied. The SOS response system was shown to play a minor role in the development of the bacterial resistance to quinolones and aminocoumarins, as well as in mutagenesis, during application of these antibiotics.