Project description:Rationale: Streptococcus pneumoniae is the most common bacterial cause of community acquired pneumonia. Some clinical trials have demonstrated a beneficial effect of corticosteroid therapy in community acquired pneumonia, but the mechanisms of this benefit remain unclear. Objectives: To investigate the biologic effects of corticosteroids in pneumococcal pneumonia in mice and in patients Methods: We studied lower respiratory tract transcriptomes from an observational cohort of mechanically ventilated patients and from a pneumonia model in mice. We also carried out comprehensive physiologic, biochemical, and histological analyses in mice to identify mechanisms of lung injury in S. pneumoniae with and without adjunctive steroid therapy. Measurement and Main Results: Transcriptomic analysis identified pleiotropic effects of steroid therapy on the lower respiratory tract in critically ill patients with pneumococcal pneumonia, findings that were reproducible in mice. In mice with pneumonia, dexamethasone in combination with ceftriaxone reduced (1) pulmonary edema formation, (2) alveolar protein permeability, (3) proinflammatory cytokine release, (4) histopathology lung injury score, and (5) hypoxemia, but did not increase bacterial burden. Conclusions: In combination with appropriate antibiotics in mice, treatment of pneumococcal pneumonia with steroid therapy reduces hypoxemia, pulmonary edema, lung permeability, and histologic criteria of lung injury, and also altered inflammatory responses at the protein and gene expression level. The concordance of transcriptional data in the mouse model and in patients with pneumococcal pneumonia supports the translational relevance of this work.
Project description:Rationale: Patients in the intensive care unit (ICU) are frequently exposed to unnecessary antibiotics. Markers of the host response to infection may aid pneumonia diagnosis and avoid antibiotic-induced complications. Objective: To assess the host response to suspected bacterial pneumonia through assessment of alveolar neutrophilia and transcriptomic profiling of alveolar macrophages. Methods: We determined the test characteristics of BAL neutrophilia for the diagnosis of bacterial pneumonia in 3 cohorts of mechanically ventilated patients. In one cohort, we also isolated alveolar macrophages from BAL fluid and used the transcriptome to identify signatures of bacterial pneumonia. Finally, we developed a humanized mouse model of Pseudomonas aeruginosa pneumonia to determine if pathogen-specific signatures can be identified in human alveolar macrophages. Measurements and Main Results: BAL neutrophilia was highly sensitive for bacterial pneumonia in both the retrospective (N = 851) and validation cohorts (N = 76 and N = 79) with a negative predictive value of over 90% when BAL neutrophil percentage was less than 50%. A transcriptional signature of bacterial pneumonia was present in both resident and recruited macrophages. Gene signatures from both cell types identified patients with bacterial pneumonia with test characteristics similar to BAL neutrophilia. Conclusions: A BAL neutrophil percentage of less than 50% is highly sensitive for bacterial pneumonia. Informative transcriptomic signatures can be generated from BAL fluid obtained during routine clinical care in the ICU. The identification of novel host response biomarkers is a promising approach to aid the diagnosis and treatment of pneumonia.
2018-11-06 | GSE121871 | GEO
Project description:Metagenomic Identification of Severe Pneumonia Pathogens in Mechanically-Ventilated Patients
| PRJNA554461 | ENA
Project description:Pseudomonas aeruginosa in mechanically ventilated patients with ventilator-associated pneumonia
Project description:We compared differential gene expression in tracheal aspirates collected mechanically ventilated subjects with COVID-19 ARDS to gene expression in tracheal aspirates from: 1) subjects with ARDS from other casues and 2) mechanically ventilated controls without evidence of pulmonary disease.
Project description:The increasing antibiotic resistance of Klebsiella pneumoniae poses a serious threat to global public health. To investigate the antibiotic resistance mechanism of Klebsiella pneumonia, we performed gene expression profiling analysis using RNA-seq data for clinical isolates of Klebsiella pneumonia, KPN16 and ATCC13883. Our results showed that mutant strain KPN16 is likely to act against the antibiotics through increased increased butanoate metabolism and lipopolysaccharide biosynthesis, and decreased transmembrane transport activity.
2023-04-18 | GSE229867 | GEO
Project description:Airway comparison in mechanically ventilated children
| PRJNA534077 | ENA
Project description:Staphylococcus aureus isolates from the respiratory track in mechanically-ventilated patients