Differential impacts of DNA repair machinery on fluoroquinolone persisters with different chromosome abundances

Juechun Tang, Allison M. Herzfeld, Gabrielle Leon, Mark P. Brynildsen

Research output: Contribution to journalArticlepeer-review


DNA repair machinery has been found to be indispensable for fluoroquinolone (FQ) persistence of Escherichia coli. Previously, we found that cells harboring two copies of the chromosome (2Chr) in stationary-phase cultures were more likely to yield FQ persisters than those with one copy of the chromosome (1Chr). Furthermore, we found that RecA and RecB were required to observe that difference, and that loss of either more significantly impacted 2Chr persisters than 1Chr persisters. To better understand the survival mechanisms of persisters with different chromosome abundances, we examined their dependencies on different DNA repair proteins. Here, we show that lexA3 and ∆recN negatively impact the abundances of 2Chr persisters to FQs, without significant impacts on 1Chr persisters. In comparison, ∆xseA, ∆xseB, and ∆uvrD preferentially depress 1Chr persistence to levels that were near the limit of detection. Collectively, these data show that the DNA repair mechanisms used by persisters vary based on chromosome number, and suggest that efforts to eradicate FQ persisters will likely have to take heterogeneity in single-cell chromosome abundance into consideration.

Original languageEnglish (US)
Issue number5
StatePublished - May 2024

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Virology


  • ciprofloxacin
  • levofloxacin
  • lexA
  • persistence
  • recN
  • uvrD
  • xseA
  • xseB


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