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Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice
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Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

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Quorum sensing-dependent virulence during Pseudomonas aeruginosa colonisation and pneumonia in mechanically

Thilo Köhler1, Raphael Guanella, Jean Carlet

  • 1Service of Infectious Diseases, University Hospital Geneva, 4 Rue Gabrielle-Perret-Gentil, Geneva 14, Switzerland.

Thorax
|August 6, 2010
PubMed
Abstract

Insights

Quorum sensing (QS) in Pseudomonas aeruginosa, particularly rhamnolipid production, is linked to ventilator-associated pneumonia (VAP) development in intubated patients. QS-proficient isolates increased VAP risk, highlighting rhamnolipids as a key virulence factor.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Critical Care Medicine

Background:

  • Pseudomonas aeruginosa is a common colonizer in intubated patients, leading to severe ventilator-associated pneumonia (VAP).
  • The role of quorum sensing (QS) in P. aeruginosa virulence during VAP development remains unclear.

Purpose of the Study:

  • To investigate the association between quorum sensing (QS) and the development of ventilator-associated pneumonia (VAP) in intubated patients.
  • To determine the role of QS-dependent virulence factors, specifically rhamnolipids, in P. aeruginosa colonization and VAP onset.

Main Methods:

  • Prospective collection of P. aeruginosa isolates and tracheal aspirates from intubated patients.
  • In vitro analysis of P. aeruginosa genotypes and QS-independent virulence factors (exoU, exoS, PAPI-1, PAPI-2).
  • Measurement of elastase and rhamnolipid production to assess QS-dependent virulence; in-patient QS gene expression analysis via RNA extraction from tracheal aspirates.

Main Results:

  • Patients colonized by QS-proficient P. aeruginosa isolates had a significantly higher risk of developing VAP (57% vs. 9%).
  • Rhamnolipid production by initial colonizing isolates was strongly associated with VAP development (p=0.003).
  • In-patient monitoring revealed induced QS gene expression in patients who developed VAP, mirroring in vitro findings.

Conclusions:

  • Rhamnolipid production by colonizing P. aeruginosa is a significant virulence factor associated with VAP development.
  • Quorum sensing activity, particularly rhamnolipid synthesis, plays a critical role in the pathogenesis of VAP.

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