AUTHOR=Li Tuodi , Wang Juan , Cao Qianqian , Li Fei , Han Jiangyuan , Zhu Bingdong , Zhang Ying , Niu Hongxia 

TITLE=Identification of Novel Genes Involved in Escherichia coli Persistence to Tosufloxacin

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.581986

DOI=10.3389/fcimb.2020.581986

ISSN=2235-2988

ABSTRACT=<p>Persisters are metabolically quiescent phenotypic variants of the wild type that are tolerant to cidal antibiotics, and the mechanisms of persister formation and survival are complex and not completely understood. To identify genes involved in persistence to tosufloxacin, which has higher activity against persisters than most other quinolones, we screened the <italic>E. coli</italic> KEIO mutant library using a different condition from most persister mutant screens (6 h) with a longer exposure of 18 h with tosufloxacin. We identified 18 mutants (<italic>acrA, acrB, ddlB, dnaG, gltI, hlpA, lpcA, recG, recN, rfaH, ruvC, surA, tatC, tolQ, uvrD, xseA</italic>, and <italic>ydfI</italic>) that failed to form tosufloxacin tolerant persisters. Among them, g<italic>ltI, hlpA, ruvC, ddlB, ydfI</italic>, and <italic>tatC</italic> are unique genes involved in <italic>E. coli</italic> persistence to tosufloxacin which have not been reported before. Furthermore, deletion mutants in genes coding periplasmic proteins (<italic>surA, lpcA, hlpA</italic>, and <italic>gltI</italic>) had more defect in persistence to tosufloxacin than the other identified mutants, with <italic>surA</italic> and <italic>lpcA</italic> mutants being the most prominent. The “deep” persister phenotype of <italic>surA</italic> and <italic>lpcA</italic> mutants was further confirmed both <italic>in vitro</italic> and <italic>in vivo</italic>. Compared with the wild type strain <italic>E. coli</italic> BW25113 <italic>in vitro</italic>, the persister phenotype of the <italic>surA</italic> and <italic>lpcA</italic> mutants was decreased more than 100–1,000-fold in persistence to various antibiotics, acidic, hyperosmotic and heat conditions. In addition, in both stationary phase bacteria and biofilm bacteria infection mouse models, the <italic>surA and lpcA</italic> mutants had lower survival and persistence than the parent uropathogenic strain UTI89, suggesting that the <italic>in vitro</italic> identified persister mechanisms (<italic>surA</italic> and <italic>lpcA</italic>) are operative and valid for <italic>in vivo</italic> persistence. Our findings provide new insight into the mechanisms of persister formation and maintenance under tosufloxacin and will likely provide novel therapeutic and vaccine targets for developing more effective treatment and prevention of persistent <italic>E. coli</italic> infections.</p>