Ploidy is an important determinant of fluoroquinolone persister survival.

TitlePloidy is an important determinant of fluoroquinolone persister survival.
Publication TypeJournal Article
Year of Publication2021
AuthorsMurawski, AM, Brynildsen, MP
JournalCurr Biol
Date Published2021 May 24
KeywordsAnti-Bacterial Agents, DNA-Binding Proteins, Escherichia coli, Escherichia coli Proteins, Exodeoxyribonuclease V, Fluoroquinolones, Ploidies, Rec A Recombinases

<p>Genetic mutants have demonstrated the importance of homologous recombination (HR) to fluoroquinolone (FQ) persistence, which suggests that single-cell chromosome (Chr) abundance might be a phenotypic variable of importance to persisters. Here, we sorted stationary-phase E. coli based on ploidy and subjected the subpopulations to tolerance assays. Subpopulations sorted to contain diploid cells harbored up to ∼40-fold more FQ persisters than those sorted to contain monoploid cells. This association was observed with distinct FQs, in independent environmental conditions, and with more than one strain of E. coli (MG1655; uropathogenic CFT073) but was abolished in HR-deficient strains (ΔrecA and ΔrecB). It was observed that the persister level of monoploid subpopulations exceeded those of ΔrecA and ΔrecB by 10-fold or more, and subsequent high-purity sorting confirmed that observation. Those data suggested the existence of distinct FQ persister subtypes: those that are and are not proficient with HR. Time-lapse microscopy revealed significant differences in initial size and growth dynamics during the post-antibiotic recovery period for persisters from monoploid- and diploid-enriched subpopulations. In addition, non-persisters in monoploid-enriched subpopulations elongated minimally following FQ treatment, resembling previous observations of HR-deficient strains, whereas non-persisters in diploid-enriched subpopulations on average filamented extensively. Together, these results identify a phenotypic variable with a significant impact on FQ persistence, establish the existence of more than one type of persister to the same antibiotic in an isogenic culture, and reveal roles for RecA and RecB in FQ persistence, even in the absence of homologous chromosomes.</p>

Alternate JournalCurr Biol
PubMed ID33711253
PubMed Central IDPMC8183807
Grant ListF30 AI140697 / AI / NIAID NIH HHS / United States
R01 AI130293 / AI / NIAID NIH HHS / United States