Related Experiment Video
Updated: May 31, 2026
Studying Microbial Communities In Vivo: A Model of Host-mediated Interaction Between Candida Albicans and Pseudomonas Aeruginosa in the Airways
Published on: January 13, 2016
Short term Candida albicans colonization reduces Pseudomonas aeruginosa-related lung injury and bacterial burden in a
Florence Ader1, Samir Jawhara, Saad Nseir
1Department of Infectious Diseases, Croix-Rousse Hospital, 104 Grande-Rue de la Croix-Rousse, Lyon, F-69004, France. florence.ader@chu-lyon.fr
Introduction:
Pseudomonas aeruginosa is a frequent cause of ventilator-acquired pneumonia (VAP). Candida tracheobronchial colonization is associated with higher rates of VAP related to P. aeruginosa. This study was designed to investigate whether prior short term Candida albicans airway colonization modulates the pathogenicity of P. aeruginosa in a murine model of pneumonia and to evaluate the effect of fungicidal drug caspofungin.
Methods:
BALB/c mice received a single or a combined intratracheal administration of C. albicans (1 × 10(5) CFU/mouse) and P. aeruginosa (1 × 10(7) CFU/mouse) at time 0 (T0) upon C. albicans colonization, and Day 2. To evaluate the effect of antifungal therapy, mice received caspofungin intraperitoneally daily, either from T0 or from Day 1 post-colonization. After sacrifice at Day 4, lungs were analyzed for histological scoring, measurement of endothelial injury, and quantification of live P. aeruginosa and C. albicans. Blood samples were cultured for dissemination.
Results:
A significant decrease in lung endothelial permeability, the amount of P. aeruginosa, and bronchiole inflammation was observed in case of prior C. albicans colonization. Mortality rate and bacterial dissemination were unchanged by prior C. albicans colonization. Caspofungin treatment from T0 (not from Day 1) increased their levels of endothelial permeability and lung P. aeruginosa load similarly to mice receiving P. aeruginosa alone.
Conclusions:
P. aeruginosa-induced lung injury is reduced when preceded by short term C. albicans airway colonization. Antifungal drug caspofungin reverses that effect when used from T0 and not from Day 1.
Insights
Prior Candida albicans airway colonization reduces Pseudomonas aeruginosa lung injury. However, early caspofungin treatment reverses this protective effect, increasing lung inflammation and bacterial load.
Area of Science:
- Microbiology
- Pulmonology
- Infectious Diseases
Background:
- Pseudomonas aeruginosa (P. aeruginosa) is a common cause of ventilator-acquired pneumonia (VAP).
- Candida (fungal) tracheobronchial colonization is linked to increased P. aeruginosa VAP rates.
Purpose of the Study:
- To determine if short-term Candida albicans (C. albicans) airway colonization affects P. aeruginosa pathogenicity in a mouse pneumonia model.
- To assess the impact of the antifungal drug caspofungin on this interaction.
Main Methods:
- Mice were intratracheally administered C. albicans and/or P. aeruginosa.
- Caspofungin treatment was administered either from the start of colonization (T0) or Day 1 post-colonization.
- Lung tissue was analyzed for histological damage, endothelial injury, and microbial load; blood was cultured for dissemination.
Main Results:
- Prior C. albicans colonization significantly decreased lung endothelial permeability, P. aeruginosa load, and bronchiole inflammation.
- Mortality and bacterial dissemination remained unaffected by prior C. albicans colonization.
- Caspofungin treatment initiated at T0, but not Day 1, increased endothelial permeability and P. aeruginosa lung burden.
Conclusions:
- Short-term C. albicans airway colonization mitigates P. aeruginosa-induced lung injury.
- Early caspofungin administration (from T0) negates the protective effect of C. albicans colonization.
