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Characterization of the virulence of Pseudomonas aeruginosa strains causing ventilator-associated pneumonia

Beatriz Alonso1,2, Laia Fernández-Barat3,4, Enea Gino Di Domenico5

  • 1Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain. beaafm@hotmail.com.

BMC Infectious Diseases
|December 2, 2020
PubMed
Abstract

Insights

Pseudomonas aeruginosa ventilator-associated pneumonia strains showed reduced virulence in a Galleria mellonella model compared to other strains. Virulence did not correlate with biofilm formation or specific genes.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Bacterial Pathogenesis

Background:

  • Ventilator-associated pneumonia (VAP) is a serious hospital-acquired infection.
  • Pseudomonas aeruginosa is a common pathogen causing VAP.
  • Understanding P. aeruginosa virulence factors is crucial for VAP treatment.

Purpose of the Study:

  • To compare virulence factors of P. aeruginosa VAP strains versus non-VAP strains.
  • To investigate the role of biofilm production, pigment, and virulence genes in P. aeruginosa VAP.
  • To assess P. aeruginosa VAP strain virulence in an in vivo model.

Main Methods:

  • Biofilm biomass and metabolic activity assessed by crystal violet and XTT assays.
  • Pyocyanin and pyoverdine production evaluated using cetrimide agar.
  • Virulence genes detected by multiplex PCR; in vivo virulence tested in Galleria mellonella.

Main Results:

  • No significant difference in biofilm production between VAP and non-VAP strains.
  • VAP strains showed no pyocyanin production after 24h (p=0.023).
  • Similar distribution of virulence genes; VAP strains exhibited lower virulence in G. mellonella (p<0.001).

Conclusions:

  • P. aeruginosa VAP virulence is independent of biofilm, pyoverdine, and certain virulence genes.
  • VAP strains display attenuated virulence compared to non-VAP strains in the G. mellonella model.
  • Findings suggest distinct pathogenic mechanisms for P. aeruginosa VAP.
Keywords:
BiofilmGalleria mellonellaPseudomonas aeruginosaVentilator-associated pneumoniaVirulence genes

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