Possible role of L-form switching in recurrent urinary tract infection

Nat Commun. 2019 Sep 26;10(1):4379. doi: 10.1038/s41467-019-12359-3.


Recurrent urinary tract infection (rUTI) is a major medical problem, especially in the elderly and infirm, but the nature of the reservoir of organisms responsible for survival and recolonisation after antibiotic treatment in humans is unclear. Here, we demonstrate the presence of cell-wall deficient (L-form) bacteria in fresh urine from 29 out of 30 older patients with rUTI. In urine, E. coli strains from patient samples readily transition from the walled state to L-form during challenge with a cell wall targeting antibiotic. Following antibiotic withdrawal, they then efficiently transition back to the walled state. E. coli switches between walled and L-form states in a zebrafish larva infection model. The results suggest that L-form switching is a physiologically relevant phenomenon that may contribute to the recurrence of infection in older patients with rUTI, and potentially other infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Cell Wall / metabolism*
  • Escherichia coli / drug effects
  • Escherichia coli / metabolism*
  • Escherichia coli / physiology
  • Escherichia coli Infections / diagnosis*
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / microbiology
  • Humans
  • Larva / microbiology
  • Recurrence
  • Risk Factors
  • Urinary Tract Infections / diagnosis*
  • Urinary Tract Infections / drug therapy
  • Urinary Tract Infections / microbiology
  • Zebrafish / microbiology


  • Anti-Bacterial Agents