Role of the flagellar hook in the structural development and antibiotic tolerance of Pseudomonas aeruginosa biofilms

Jules D. P. Valentin, Herve Straub, Franziska Pietsch, Marion Lemare, Christian H. Ahrens, Frank Schreiber, Jeremy S. Webb, Henny C. van der Mei, Qun Ren*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)
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Abstract

Pseudomonas aeruginosa biofilms exhibit an intrinsic resistance to antibiotics and constitute a considerable clinical threat. In cystic fibrosis, a common feature of biofilms formed by P. aeruginosa in the airway is the occurrence of mutants deficient in flagellar motility. This study investigates the impact of flagellum deletion on the structure and antibiotic tolerance of P. aeruginosa biofilms, and highlights a role for the flagellum in adaptation and cell survival during biofilm development. Mutations in the flagellar hook protein FlgE influence greatly P. aeruginosa biofilm structuring and antibiotic tolerance. Phenotypic analysis of the flgE knockout mutant compared to the wild type (WT) reveal increased fitness under planktonic conditions, reduced initial adhesion but enhanced formation of microcolony aggregates in a microfluidic environment, and decreased expression of genes involved in exopolysaccharide formation. Biofilm cells of the flgE knock-out mutant display enhanced tolerance towards multiple antibiotics, whereas its planktonic cells show similar resistance to the WT. Confocal microscopy of biofilms demonstrates that gentamicin does not affect the viability of cells located in the inner part of the flgE knock-out mutant biofilms due to reduced penetration. These findings suggest that deficiency in flagellar proteins like FlgE in biofilms and in cystic fibrosis infections represent phenotypic and evolutionary adaptations that alter the structure of P. aeruginosa biofilms conferring increased antibiotic tolerance.

Original languageEnglish
Number of pages11
JournalISME Journal
Early online date8-Dec-2021
DOIs
Publication statusPublished - 2022

Keywords

  • 2-COMPONENT REGULATORY SYSTEM
  • MULTICELLULAR STRUCTURES
  • TWITCHING MOTILITY
  • BACTERIAL BIOFILMS
  • GENE-EXPRESSION
  • NITRIC-OXIDE
  • POLYMYXIN-B
  • IV PILI
  • RESISTANCE
  • INVOLVEMENT

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