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Evolution and adaptation in Pseudomonas aeruginosa biofilms driven by mismatch repair system-deficient mutators

Adela M Luján1, María D Maciá, Liang Yang

  • 1Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.

Plos One
|November 25, 2011
PubMed

Insights

Pseudomonas aeruginosa mutator strains, deficient in mismatch repair, show enhanced adaptability in biofilms, not planktonic cultures. This biofilm advantage fuels adaptive evolution in chronic infections.

Area of Science:

  • Microbiology
  • Genetics
  • Infectious Diseases

Background:

  • Pseudomonas aeruginosa is a major opportunistic pathogen causing chronic airway infections, particularly in cystic fibrosis (CF) patients.
  • Chronic P. aeruginosa infections are difficult to eradicate and involve biofilm development, phenotypic diversification, and mutator phenotypes (defective mismatch repair system - MRS).
  • The interplay between these adaptive strategies in P. aeruginosa chronic infections remains poorly understood.

Purpose of the Study:

  • To investigate the impact of the mutS-associated mutator phenotype on the development, dynamics, diversification, and adaptation of P. aeruginosa biofilms.
  • To compare the adaptability of MRS-deficient mutator strains versus wild-type strains in structured biofilms and planktonic cultures.

Main Methods:

  • Utilized the flow-cell biofilm model system for controlled biofilm growth.
  • Conducted competition experiments between mutator and wild-type P. aeruginosa strains.
  • Analyzed biofilm architecture and characterized morphotypic colony variants.

Main Results:

  • MRS-deficient P. aeruginosa mutators exhibited enhanced adaptability in structured biofilms compared to wild-type strains, but not in planktonic cultures.
  • Mutator biofilms showed accelerated micro-colony development and increased rates of phenotypic diversification.
  • Generated morphotypic variants from mutator biofilms displayed greater competitiveness, indicating enhanced adaptive evolution.

Conclusions:

  • The mutator phenotype confers a significant adaptive advantage to P. aeruginosa within the biofilm environment.
  • This study elucidates the role of mutators in P. aeruginosa adaptive evolution during chronic biofilm infections.
  • Findings contribute to understanding the high prevalence and importance of mutators in chronic P. aeruginosa infections.

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