PT - JOURNAL ARTICLE AU - Svenningsen, Mikkel Skjoldan AU - Svenningsen, Sine Lo AU - Sørensen, Michael Askvad AU - Mitarai, Namiko TI - Existence of log-phase Escherichia coli persisters and lasting memory of a starvation pulse AID - 10.1101/2020.09.17.301598 DP - 2021 Jan 01 TA - bioRxiv PG - 2020.09.17.301598 4099 - http://biorxiv.org/content/early/2021/09/28/2020.09.17.301598.short 4100 - http://biorxiv.org/content/early/2021/09/28/2020.09.17.301598.full AB - The vast majority of a bacterial population is quickly killed when treated with a lethal concentration of antibiotics. The time scale of this killing is often comparable with the bacterial generation time before addition of antibiotics. Yet, a small subpopulation typically survives for an extended period. However, the long-term killing dynamics of bacterial cells has not been fully quantified even in well-controlled laboratory conditions. We constructed a week-long killing assay and followed the survival fraction of Escherichia coli K12 exposed to a high concentration of ciprofloxacin. We found that long-term survivors were formed during exponential growth, with some cells surviving at least 7 days. The long-term dynamics contained at least three timescales, which greatly enhances predictions of the population survival time compared to the biphasic extrapolation from the short term behavior. Furthermore, we observed a surprisingly long memory effect of a brief carbon starvation pulse, which was dependent on the (p)ppGpp synthase relA. Specifically, one hour of carbon starvation prior to antibiotics exposure increased the surviving fraction by nearly 100-fold even after 4 days of ciprofloxacin treatment.Competing Interest StatementThe authors have declared no competing interest.