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Reduced expression of virulence factors in multidrug-resistant Pseudomonas aeruginosa strains

Aleksander Deptuła1, Eugenia Gospodarek

  • 1Department of Microbiology, Nicolaus Copernicus University, Collegium Medicum in Bydgoszcz, 9 M. Skłodowskiej, Curie St., Bydgoszcz, Poland. deptul@o2.pl

Archives of Microbiology
|December 5, 2009
PubMed

Insights

Multidrug-resistant Pseudomonas aeruginosa strains exhibit reduced virulence. These antibiotic-resistant bacteria show impaired growth and lower production of key virulence factors compared to their susceptible counterparts.

Area of Science:

  • Microbiology
  • Bacterial genetics
  • Infectious diseases

Background:

  • Increasing isolation of multidrug-resistant (MDR) Pseudomonas aeruginosa from clinical settings.
  • Antibiotic resistance acquisition may impose a physiological cost on bacteria.
  • Limited data comparing phenotypic traits of MDR and multidrug-susceptible (MDS) P. aeruginosa.

Purpose of the Study:

  • To investigate and compare phenotypic differences between MDR and MDS clinical isolates of P. aeruginosa.
  • To assess the impact of multidrug resistance on bacterial physiology and virulence factors.

Main Methods:

  • Analysis of 150 clinical P. aeruginosa isolates (75 MDR, 75 MDS).
  • Phenotypic characterization including adherence to polystyrene, growth rate, alginate production, extracellular matrix binding, lipolytic, elastase, LasA protease, phospholipase C activity, pyocyanin production, and proteolytic activity.
  • Pulsed-field gel electrophoresis (PFGE) used for isolate relatedness assessment.

Main Results:

  • MDR strains showed significantly lower adherence to polystyrene and reduced growth rates in liquid media compared to MDS strains.
  • MDR strains produced significantly lower amounts of extracellular material binding Congo Red, reduced lipolytic, elastase, LasA protease, phospholipase C activity, and pyocyanin.
  • No significant difference in proteolytic activity was observed between MDR and MDS strains.
  • Alginate was detected in a similar proportion of both MDR and MDS strains.

Conclusions:

  • MDR P. aeruginosa strains exhibit impaired virulence compared to MDS strains.
  • The acquisition of multidrug resistance is associated with a biological cost, manifesting as reduced physiological fitness and virulence.
  • Findings highlight potential therapeutic strategies targeting virulence in MDR P. aeruginosa infections.

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