Project description:This project was a prospective translational study aimed at evaluating gene expression profiles (GEP) of patients with ventilator-associated pneumonia (VAP) . GEP of VAP were compared with a control group of patients which did not developed ventilator-associated lower respiratory tract infection despite being subjected to mechanical ventilation.
Project description:The onset of an infection-specific transcriptional program precedes the clinical diagnosis in patients who developed Ventilator-associated pneumonia (VAP). Ventilator-associated tracheobronchitis (VAT) is another respiratory infection affecting<br><br>outcomes in intubated patients, but interactions between VAT and VAP remains unknown.
Project description:Ventilator-associated pneumonia (VAP) is a healthcare-acquired infection arising from the invasion of the lower respiratory tract by opportunistic pathogens in ventilated patients. The current method of diagnosis requires the culture of an airway sample such as bronchoalveolar lavage, which is invasive to obtain and may take up to seven days to identify a causal pathogen, or indeed rule out infection. While awaiting results, patients are administered empirical antibiotics; risks of this approach include lack of effect on the causal pathogen, contribution to the development of antibiotic resistance and downstream effects such as increased length of intensive care stay, cost, morbidity and mortality. Specific biomarkers which could identify causal pathogens in a timely manner are needed as they would allow judicious use of the most appropriate antimicrobial therapy. Volatile organic compound (VOC) analysis in exhaled breath is proposed as an alternative due to its non-invasive nature and its potential to provide rapid diagnosis at the patient's bedside. VOCs in exhaled breath originate from exogenous, endogenous, as well as microbial sources. To identify potential markers, VAP-associated pathogens Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus were cultured in both artificial sputum medium and nutrient broth, and their headspaces were sampled and analysed for VOCs. Previously reported volatile markers were identified in this study, including indole and 1-undecene, alongside compounds that are novel to this investigation, cyclopentanone and 1-hexanol. We further investigated media components (substrates) to identify those that are essential for indole and cyclopentanone production, with potential implications for understanding microbial metabolism in the lung.
Project description:CF patients suffer from chronic and recurrent respiratory tract infections which eventually lead to lung failure followed by death. Pseudomonas aeruginosa is one of the major pathogens for CF patients and is the principal cause of mortality and morbidity in CF patients. Once it gets adapted, P. aeruginosa can persist for several decades in the respiratory tracts of CF patients, overcoming host defense mechanisms as well as intensive antibiotic therapies.
Project description:We preformed a systems biological assessment of lower respiratory tract host immune responses and microbiome dynamics in COVD-19 patients, using bulk RNA-sequencing, single-cell RNA sequencing, and techniques, and microbiome analysis. Are focus was on differential gene expression in severe COVID-19 patients who developed ventilator associated pneumonia (VAP) during their course versus severe COVID-19 patients who did not develop VAP. We found early impairment in antibacterial immune signaling in patients two or more weeks prior to the development of VAP, compared to COVID-19 patients who did not develop VAP. There was no signficant difference in viral load, but an association of disruption in lung microbiome by alpha and beta diversity metrics was also found.
Project description:We preformed a systems biological assessment of lower respiratory tract host immune responses and microbiome dynamics in COVD-19 patients, using bulk RNA-sequencing, single-cell RNA sequencing, and techniques, and microbiome analysis. Are focus was on differential gene expression in severe COVID-19 patients who developed ventilator associated pneumonia (VAP) during their course versus severe COVID-19 patients who did not develop VAP. We found early impairment in antibacterial immune signaling in patients two or more weeks prior to the development of VAP, compared to COVID-19 patients who did not develop VAP. There was no signficant difference in viral load, but an association of disruption in lung microbiome by alpha and beta diversity metrics was also found.
Project description:CF patients suffer from chronic and recurrent respiratory tract infections which eventually lead to lung failure followed by death. Pseudomonas aeruginosa is one of the major pathogens for CF patients and is the principal cause of mortality and morbidity in CF patients. Once it gets adapted, P. aeruginosa can persist for several decades in the respiratory tracts of CF patients, overcoming host defense mechanisms as well as intensive antibiotic therapies. P. aeruginosa CF strains isolated from different infection stage were selected for RNA extraction and hybridization on Affymetrix microarrays. Two batch of P. aeruginosa CF isolates are chosen : 1) isolates from a group of patients since 1973-2008 as described in ref (PMID: 21518885); 2) isolates from a group of newly infected children as described in ref (PMID: 20406284).
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.