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:Objective: Identify genes that are differentially expressed between critically ill trauma patients who go on to develop ventilator-associated pneumonia (VAP) compared to similar patients who do not develop VAP Using gene expression differences, develop a model that predicts which patients are at greater risk of developing VAP. Prospective observational study, analysis of gene expression in 20 patient samples, 10 that developed ventilator-associated pneumonia, 10 that did not
Project description:Ventilator associated pneumonia (VAP) is the 2nd most common hospital acquired infection associated with high morbidity, mortality and increased hospitalization. Current practice of diagnosis is based on clinical symptoms and bronchoalvolar lavage (BAL) culture. The procedures of BAL collections are invasive whereas, endotracheal aspirate (ETA), a matrix of upper airway collection is minimally invasive and underexplored in VAP diagnosis. The study describes first in detail characterization of proteome of longitudinal ETA collections from 16 intubated patients including 11 VAP patients and explores potential utility of ETA in VAP diagnosis.
Project description:Objective: Identify genes that are differentially expressed between critically ill trauma patients who go on to develop ventilator-associated pneumonia (VAP) compared to similar patients who do not develop VAP Using gene expression differences, develop a model that predicts which patients are at greater risk of developing VAP.
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:PurposeTo compare bacteria recovered by standard cultures and metataxonomics, particularly with regard to ventilator-associated pneumonia (VAP) pathogens, and to determine if the presence of particular bacteria or microbiota in tracheal and oropharyngeal secretions during the course of intubation was associated with the development of VAP.MethodsIn this case-control study, oropharyngeal secretions and endotracheal aspirate were collected daily in mechanically ventilated patients. Culture and metataxonomics (16S rRNA gene-based taxonomic profiling of bacterial communities) were performed on serial upper respiratory samples from patients with late-onset definite VAP and their respective controls.ResultsMetataxonomic analyses showed that a low relative abundance of Bacilli at the time of intubation in the oropharyngeal secretions was strongly associated with the subsequent development of VAP. On the day of VAP, the quantity of human and bacterial DNA in both tracheal and oropharyngeal secretions was significantly higher in patients with VAP than in matched controls with similar ventilation times. Molecular techniques identified the pathogen(s) of VAP found by culture, but also many more bacteria, classically difficult to culture, such as Mycoplasma spp. and anaerobes.ConclusionsMolecular analyses of respiratory specimens identified markers associated with the development of VAP, as well as important differences in the taxa abundance between VAP and controls. Further prospective trials are needed to test the predictive value of these markers, as well as the relevance of uncultured bacteria in the pathogenesis of VAP.
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:Rationale: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and hospitalizations in infants worldwide. Known risk factors, however, incompletely explain the variability of RSV disease severity among children. We postulate that severity of RSV infection is influenced in part by modulation of the host immune response by the local microbial ecosystem at the time of infection. Objectives: To define whether different nasopharyngeal microbiota profiles are associated with distinct host transcriptome profiles and severity in children with RSV infection. Methods: We analyzed the nasopharyngeal microbiota profiles of young children with mild and severe RSV disease and healthy matched controls by 16S-rRNA sequencing. In parallel, we analyzed whole blood gene expression profiles to study the relationship between microbial community composition, the RSV-induced host transcriptional response and clinical disease severity. Measurements and Main results: We identified five nasopharyngeal microbiota profiles characterized by enrichment of H. influenzae, Streptococcus, Corynebacterium, Moraxella or S. aureus. RSV infection and RSV hospitalization were positively associated with H. influenzae and Streptococcus, and negatively associated with S. aureus abundance, independent of age. The host response to RSV was defined by overexpression of interferon-related genes, and this was independent of the microbiota composition. On the other hand, transcriptome profiles of RSV infected children with H. influenzae and Streptococcus-dominated microbiota were characterized by greater overexpression of genes linked to toll-like receptor-signaling and neutrophil activation and were more frequently hospitalized Conclusions: Our data suggest an immunomodulatory role for the resident nasopharyngeal microbial community early in RSV infection, potentially affecting RSV disease severity.
Project description:Purpose: The aim of this study is to determine the expression profile in whole blood samples of children infected with respiratory syncytial virus and other respiratory viruses. Method: Host mRNA profiles in whole blood samples of children were generated by next-generation sequencing using Illumina Hiseq. Sequence reads were trimmed for adapter using skewer, mapped to reference human genome using STAR, and quantified using RSEM. Differential expression analysis was performed using DESeq2. Results: Transcriptional module analysis revealed dysregulation of genes related to inflammatory response, neutrophils, monocytes, B-cell and T-cell response. Conclusion: This study showed an imbalance in innate and adaptive immune responses in children with respiratory virus infections. This study also showed that NGS provides a comprehensive assessment of transcripts in whole blood samples.