RESUMEN

Regardless of their targets and modes of action, subinhibitory concentrations of antibiotics can have an impact on cell physiology and trigger a large variety of cellular responses in different bacterial species. Subinhibitory concentrations of ß-lactam antibiotics cause reactive oxygen species production and induce PolIV-dependent mutagenesis in Escherichia coli. Here we show that subinhibitory concentrations of ß-lactam antibiotics induce the RpoS regulon. RpoS-regulon induction is required for PolIV-dependent mutagenesis because it diminishes the control of DNA-replication fidelity by depleting MutS in E. coli, Vibrio cholerae and Pseudomonas aeruginosa. We also show that in E. coli, the reduction in mismatch-repair activity is mediated by SdsR, the RpoS-controlled small RNA. In summary, we show that mutagenesis induced by subinhibitory concentrations of antibiotics is a genetically controlled process. Because this mutagenesis can generate mutations conferring antibiotic resistance, it should be taken into consideration for the development of more efficient antimicrobial therapeutic strategies.

Asunto(s)

Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Proteínas Bacterianas/fisiología , Replicación del ADN/efectos de los fármacos , Mutagénesis , Factor sigma/fisiología , beta-Lactamas/farmacología , Bacterias/genética , Replicación del ADN/fisiología , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Vibrio cholerae/efectos de los fármacos , Vibrio cholerae/genética , Vibrio cholerae/metabolismo