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Updated: Mar 10, 2026
Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
Published on: January 17, 2014
Analysis of the intestinal microbial community and inferred functional capacities during the host response to
Derrick R Samuelson1, Tysheena P Charles1, Nicholas M de la Rua1
1a Section of Pulmonary/Critical Care & Allergy/Immunology, Department of Medicine , Louisiana State University Health Sciences Center , New Orleans , Louisiana , USA.
Background:
Pneumocystis pneumonia is a major cause of morbidity and mortality in patients infected with HIV/AIDS. In this study, we evaluated the intestinal microbial communities associated with the development of experimental Pneumocystis pneumonia, as there is growing evidence that the intestinal microbiota is critical for host defense against fungal pathogens.
Methods:
C57BL/6 mice were infected with live Pneumocystis murina (P. murina) via intratracheal inoculation and sacrificed 7 and 14 days postinfection for microbiota analysis. In addition, we evaluated the intestinal microbiota from CD4+ T cell depleted mice infected with P. murina.
Results:
We found that the diversity of the intestinal microbial community was significantly altered by respiratory infection with P. murina. Specifically, mice infected with P. murina had altered microbial populations, as judged by changes in diversity metrics and relative taxa abundances. We also found that CD4+ T cell depleted mice infected with P. murina exhibited significantly altered intestinal microbiota that was distinct from immunocompetent mice infected with P. murina, suggesting that loss of CD4+ T cells may also affects the intestinal microbiota in the setting of Pneumocystis pneumonia. Finally, we employed a predictive metagenomics approach to evaluate various microbial features. We found that Pneumocystis pneumonia significantly alters the intestinal microbiota's inferred functional potential for carbohydrate, energy, and xenobiotic metabolism, as well as signal transduction pathways.
Conclusions:
Our study provides insight into specific-microbial clades and inferred microbial functional pathways associated with Pneumocystis pneumonia. Our data also suggest a role for the gut-lung axis in host defense in the lung.
Insights
Pneumocystis pneumonia alters gut microbial communities, impacting metabolism and host defense. This research highlights the gut-lung axis connection in fungal infections.
Area of Science:
- Microbiology
- Immunology
- Host-Pathogen Interactions
Background:
- Pneumocystis pneumonia (PCP) is a significant cause of illness and death in HIV/AIDS patients.
- The intestinal microbiota plays a crucial role in host defense against fungal infections.
Purpose of the Study:
- To investigate the intestinal microbial communities associated with experimental Pneumocystis pneumonia.
- To understand the impact of CD4+ T cell depletion on the gut microbiota during PCP.
Main Methods:
- Mice were infected with Pneumocystis murina (P. murina) via intratracheal inoculation.
- Intestinal microbiota was analyzed at 7 and 14 days postinfection.
- Predictive metagenomics was used to assess microbial functional potential.
Main Results:
- P. murina infection significantly altered intestinal microbial diversity and taxa abundance.
- CD4+ T cell depletion led to distinct changes in the gut microbiota during PCP.
- PCP infection altered the inferred functional potential of the gut microbiota, affecting metabolism and signal transduction pathways.
Conclusions:
- The study identifies specific microbial clades and functional pathways linked to PCP.
- Findings suggest a role for the gut-lung axis in pulmonary host defense against fungal pathogens.
