Superfast Evolution of Multi-drug Antibiotic Resistance

In the presence of antibiotics, SOS response supports bacteria survival by activating the DNA repair system. Here, we find that the reduction of the SOS response by deletion of its master regulator recA can cause an even superfast establishment of antibiotic resistance (20-fold MIC) in Escherichia coli, which only takes 8 hours after a single exposure to ampicillin. And the gene acrB mutations were observed with a multi-drug resistance to other classes of antibiotics. This process is accompanied with the rapidly occurring DNA mutations, but orthogonal to the SOS response. ### Competing Interest Statement The authors have declared no competing interest.