Related Experiment Video

Updated: Mar 28, 2026

A Visual Assay to Monitor T6SS-mediated Bacterial Competition
08:45

A Visual Assay to Monitor T6SS-mediated Bacterial Competition

Published on: March 20, 2013

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T6SS mutants exploit itaconate to support infection of phagocytes

Ayesha Z Beg1, Blanche L Fields1, Ying-Tsun Chen1

  • 1Department of Pediatrics, Columbia University, New York, NY, USA.

Biorxiv : the Preprint Server for Biology
|March 27, 2026
PubMed

Insights

Pseudomonas aeruginosa variants lacking H3-T6SS cause chronic pneumonia by persisting within macrophages. Itaconate fuels their survival and metabolism, enabling intractable lung infections.

Area of Science:

  • Microbiology
  • Immunology
  • Pulmonary Medicine

Background:

  • Pseudomonas aeruginosa frequently causes persistent pneumonias resistant to antibiotics.
  • Chronic P. aeruginosa pneumonia is associated with specific bacterial variants.

Purpose of the Study:

  • To investigate the role of H3-T6SS deficiency in P. aeruginosa chronic pneumonia.
  • To understand the mechanisms enabling bacterial persistence within host macrophages.

Main Methods:

  • Comparative analysis of P. aeruginosa strains from acute vs. chronic pneumonia patients.
  • Murine lung infection model using wild-type and H3-T6SS mutant strains.
  • In vitro macrophage assays to assess bacterial uptake, survival, and metabolic activity.

Main Results:

  • H3-T6SS deficient P. aeruginosa variants were found in chronic pneumonia patients.
  • A H3-T6SS mutant showed increased virulence in a murine lung infection model.
  • Mutants exhibited enhanced intracellular survival and metabolic adaptation within macrophages, particularly in the presence of itaconate.
  • Itaconate was crucial for maintaining macrophage viability and optimizing bacterial respiration and carbon source utilization.

Conclusions:

  • Loss of H3-T6SS function promotes metabolic versatility in P. aeruginosa.
  • This adaptation enables the bacteria to persist within macrophages, leading to intractable pulmonary infections.
  • Targeting bacterial metabolic pathways within the phagolysosome could be a therapeutic strategy.

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