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Updated: Jan 28, 2026
Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice
Published on: March 17, 2014
Breath metabolome of mice infected with Pseudomonas aeruginosa
Giorgia Purcaro1,2, Mavra Nasir3, Flavio A Franchina1,4
1Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA.
Introduction:
The measurement of specific volatile organic compounds in breath has been proposed as a potential diagnostic for a variety of diseases. The most well-studied bacterial lung infection in the breath field is that caused by Pseudomonas aeruginosa.
Objectives:
To determine a discriminatory core of molecules in the "breath-print" of mice during a lung infection with four strains of P. aeruginosa (PAO1, PA14, PAK, PA7). Furthermore, we attempted to extrapolate a strain-specific "breath-print" signature to investigate the possibility of recapitulating the genetic phylogenetic groups (Stewart et al. Pathog Dis 71(1), 20-25, 2014. https://doi.org/10.1111/2049-632X.12107 ).
Methods:
Breath was collected into a Tedlar bag and shortly after drawn into a thermal desorption tube. The latter was then analyzed into a comprehensive multidimensional gas chromatography coupled with a time-of-flight mass spectrometer. Random forest algorithm was used for selecting the most discriminatory features and creating a prediction model.
Results:
Three hundred and one molecules were significantly different between animals infected with P. aeruginosa, and those given a sham infection (PBS) or inoculated with UV-killed P. aeruginosa. Of those, nine metabolites could be used to discriminate between the three groups with an accuracy of 81%. Hierarchical clustering showed that the signature from breath was due to a specific response to live bacteria instead of a generic infection response. Furthermore, we identified ten additional volatile metabolites that could differentiate mice infected with different strains of P. aeruginosa. A phylogram generated from the ten metabolites showed that PAO1 and PA7 were the most distinct group, while PAK and PA14 were interspersed between the former two groups.
Conclusions:
To the best of our knowledge, this is the first study to report on a 'core' murine breath print, as well as, strain level differences between the compounds in breath. We provide identifications (by running commercially available analytical standards) to five breath compounds that are predictive of P. aeruginosa infection.
Insights
This study identified a core breathprint for Pseudomonas aeruginosa lung infections in mice, distinguishing between live bacteria and infection responses. Specific volatile metabolites also differentiated between bacterial strains, aiding in diagnostics.
Area of Science:
- Microbiology
- Analytical Chemistry
- Biomarker Discovery
Background:
- Volatile organic compounds (VOCs) in breath show promise for disease diagnostics.
- Pseudomonas aeruginosa (P. aeruginosa) is a well-studied bacterial lung pathogen relevant to breath analysis.
Purpose of the Study:
- To identify a core set of VOCs in mouse breath indicative of P. aeruginosa infection.
- To determine if specific VOCs can differentiate between P. aeruginosa strains.
- To investigate the potential for strain-specific breathprint signatures.
Main Methods:
- Breath samples collected from infected and control mice.
- Analysis using comprehensive multidimensional gas chromatography-time-of-flight mass spectrometry.
- Random forest algorithm applied for feature selection and model creation.
Main Results:
- 301 VOCs differed between infected and control groups; nine metabolites discriminated with 81% accuracy.
- Breath signature indicated a specific response to live bacteria.
- Ten VOCs differentiated between P. aeruginosa strains, forming a phylogram.
Conclusions:
- First study to report a core murine breathprint and strain-level VOC differences for P. aeruginosa.
- Identified five breath compounds predictive of P. aeruginosa infection.
- Breath analysis offers potential for diagnosing P. aeruginosa infections and strain typing.
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