The proximity and continuity of the oral cavity and the lower respiratory tract allows the oropharyngeal microbiome to be a major determinant of the lung microbiome. In addition, host‐pathogen ...interactions related to the oropharyngeal microbiome or its metabolites could propagate systemic inflammation or modulate host defense mechanisms that could affect other organs, including the lung. There is increasing appreciation of the pathophysiologic significance of the lung microbiome, not only in the classical infection‐related diseases, pneumonia, bronchiectasis, and cystic fibrosis, but also in chronic noninfectious lung diseases, such as chronic obstructive pulmonary disease, asthma, and pulmonary fibrosis. In this review, we will explore the relationship of the oral microbiome with lung diseases, such as pneumonia, chronic obstructive pulmonary disease, asthma, and cystic fibrosis.
COPD and the microbiome Mammen, Manoj J; Sethi, Sanjay
Respirology (Carlton, Vic.),
20/May , Letnik:
21, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Traditional culture techniques confirm that bacteria have an important role in Chronic Obstructive Pulmonary Disease (COPD). In individuals with COPD, acquisition of novel bacterial strains is ...associated with onset of acute exacerbation of COPD, which leads to further lung dysfunction and enormous health-care costs. Recent study of the human microbiome, the total composite of the bacteria on the human body, posited the microbiome as the last human organ studied, as the microbiome performs a multitude of metabolic functions absent in the human genome. The largest project to study the human microbiome was the National Institutes of Health (NIH) human microbiome project (HMP) started in 2007 to understand the 'normal' microbiome. However due to the presumption that the healthy human lung was sterile, the respiratory tract was not included in that study. The advent of next-generation sequencing technologies has allowed the investigation of the human respiratory microbiome, which revealed that the healthy lung does have a robust microbiome. Subsequent studies in individuals with COPD revealed that the microbiome composition fluctuates with severity of COPD, composition of the individual aero-digestive tract microbiomes, age, during an acute exacerbation of COPD and with the use of steroids and/or antibiotics. Understanding the impact of the microbiome on COPD progression and risk of exacerbation will lead to directed therapies for prevention of COPD progression and exacerbation.
Objectives
Our objective was to evaluate patient‐reported oxygen saturation (SpO2) using pulse oximetry as a home monitoring tool for patients with initially nonsevere COVID‐19 to identify need for ...hospitalization.
Methods
Patients were enrolled at the emergency department (ED) and outpatient testing centers. Each patient was given a home pulse oximeter and instructed to record their SpO2 every 8 hours. Patients were instructed to return to the ED for sustained home SpO2 < 92% or if they felt they needed emergent medical attention. Relative risk was used to assess the relation between hospitalization and home SpO2 < 92% in COVID‐19–positive patients.
Results
We enrolled 209 patients with suspected COVID‐19, of whom 77 patients tested positive for COVID‐19 and were included. Subsequent hospitalization occurred in 22 of 77 (29%) patients. Resting home SpO2 < 92% was associated with an increased likelihood of hospitalization compared to SpO2 ≥ 92% (relative risk = 7.0, 95% confidence interval = 3.4 to 14.5, p < 0.0001). Home SpO2 < 92% was also associated with increased risk of intensive care unit admission, acute respiratory distress syndrome, and septic shock. In our cohort, 50% of patients who ended up hospitalized only returned to the ED for incidental finding of low home SpO2 without worsening of symptoms. One‐third (33%) of nonhospitalized patients stated that they would have returned to the ED if they did not have a pulse oximeter to reassure them at home.
Conclusions
This study found that home pulse oximetry monitoring identifies need for hospitalization in initially nonsevere COVID‐19 patients when a cutoff of SpO2 92% is used. Half of patients who ended up hospitalized had SpO2 < 92% without worsening symptoms. Home SpO2 monitoring also reduces unnecessary ED revisits.
Specific bacterial species are implicated in the pathogenesis of exacerbations of chronic obstructive pulmonary disease (COPD). However, recent studies of clinically stable COPD patients have ...demonstrated a greater diversity of airway microbiota, whose role in acute exacerbations is unclear. In this study, temporal changes in the airway microbiome before, at the onset of, and after an acute exacerbation were examined in 60 sputum samples collected from subjects enrolled in a longitudinal study of bacterial infection in COPD. Microbiome composition and predicted functions were examined using 16S rRNA-based culture-independent profiling methods. Shifts in the abundance (≥ 2-fold, P < 0.05) of many taxa at exacerbation and after treatment were observed. Microbiota members that were increased at exacerbation were primarily of the Proteobacteria phylum, including nontypical COPD pathogens. Changes in the bacterial composition after treatment for an exacerbation differed significantly among the therapy regimens clinically prescribed (antibiotics only, oral corticosteroids only, or both). Treatment with antibiotics alone primarily decreased the abundance of Proteobacteria, with the prolonged suppression of some microbiota members being observed. In contrast, treatment with corticosteroids alone led to enrichment for Proteobacteria and members of other phyla. Predicted metagenomes of particular microbiota members involved in these compositional shifts indicated exacerbation-associated loss of functions involved in the synthesis of antimicrobial and anti-inflammatory products, alongside enrichment in functions related to pathogen-elicited inflammation. These trends reversed upon clinical recovery. Further larger studies will be necessary to determine whether specific compositional or functional changes detected in the airway microbiome could be useful indicators of exacerbation development or outcome.
The healthy lung has previously been considered to be a sterile organ because standard microbiological culture techniques consistently yield negative results. However, culture-independent techniques ...report that large numbers of microorganisms coexist in the lung. There are many unknown aspects in the field, but available reports show that the lower respiratory tract microbiota: 1) is similar in healthy subjects to the oropharyngeal microbiota and dominated by members of the Firmicutes, Bacteroidetes and Proteobacteria phyla; 2) shows changes in smokers and well-defined differences in chronic respiratory diseases, although the temporal and spatial kinetics of these changes are only partially known; and 3) shows relatively abundant non-cultivable bacteria in chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis and bronchiectasis, with specific patterns for each disease. In all of these diseases, a loss of diversity, paralleled by an over-representation of Proteobacteria (dysbiosis), has been related to disease severity and exacerbations. However, it is unknown whether dysbiosis is a cause or a consequence of the damage to bronchoalveolar surfaces.Finally, little is known about bacterial functionality and the interactions between viruses, fungi and bacteria. It is expected that future research in bacterial gene expressions, metagenomics longitudinal analysis and host-microbiome animal models will help to move towards targeted microbiome interventions in respiratory diseases.
Infectious agents are a major cause of acute exacerbations of chronic bronchitis (AECB) and COPD. Several respiratory viruses are associated with 30% of exacerbations, with or without a superimposed ...bacterial infection. Atypical bacteria, mostly Chlamydia pneumoniae, have been implicated in < 10% of AECB. The role of bacterial pathogens when isolated from the respiratory tract during AECB has become better defined by application of several newer investigative techniques. Bacterial pathogens can be isolated in significant concentrations from distal airways in 50% of AECB. Specific immune responses to surface exposed antigens of the infecting pathogen have been shown to develop after an exacerbation. Emerging evidence from molecular epidemiology and measurement of airway inflammation further support the role of bacteria in AECB. When properly defined, 80% of AECB are likely to be infectious in origin.
Coronavirus disease 2019 (COVID-19), caused by the highly contagious novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a worldwide pandemic and currently represents ...a major public health issue. COVID-19 has highlighted the need for clear and accurate guidance on the use of aerosol-generating procedures, such as nebulization, for the treatment of patients with respiratory diseases with or without COVID-19. Despite the lack of evidence, there is heightened concern about the potential risk of transmission of SARS-CoV-2 in the form of aerosolized respiratory droplets during the nebulized treatment of patients with COVID-19. Consequently, the use of metered-dose inhalers (MDIs) has risen considerably as an alternative to nebulized therapy, which has led to inadequate supplies of MDIs in some parts of the United States. In this article, we review and discuss the role of nebulization in patients with SARS-CoV-2 and the treatment of noninfected patients with chronic respiratory diseases. The following two important questions are addressed: (1) should nebulized therapy be used in hospital or home settings by patients infected with SARS-CoV-2; and (2) should nebulized therapy be continued in patients already using it for chronic respiratory disease management in hospital or home settings?
The reviews of this paper are available via the supplemental material section.
Understanding the causes and factors related to readmission for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) within a nationwide database including all payers and ages can ...provide valuable input for the development of generalizable readmission reduction strategies.
To determine the rates, causes, and predictors for early (3-, 7-, and 30-d) readmission in patients hospitalized with AECOPD in the United States using the Nationwide Readmission Database after the initiation of the Hospital Readmissions Reduction Program, but before its expansion to COPD.
We conducted an analysis of the Nationwide Readmission Database from 2013 to 2014. Index admissions and readmissions for an AECOPD were defined consistent with Hospital Readmissions Reduction Program guidelines. We investigated the percentage of 30-day readmissions occurring each day after discharge and the most common readmission diagnoses at different time periods after hospitalization. The relationship between predictors (categorized as patient, clinical, and hospital factors) and early readmission were evaluated using a hierarchical two-level logistic model. To examine covariate effects on early-day readmission, predictors for 3-, 7-, and 30-day readmissions were modeled separately.
There were 202,300 30-day readmissions after 1,055,830 index AECOPD admissions, a rate of 19.2%. The highest readmission rates (4.2-5.5%) were within the first 72 hours of discharge, and 58% of readmissions were within the first 15 days. Respiratory-based diseases were the most common reasons for readmission (52.4%), and COPD was the most common diagnosis (28.4%). Readmission diagnoses were similar at different time periods after discharge. Early readmission was associated with patient (Medicaid payer status, lower household income, and higher comorbidity burden) and clinical factors (longer length of stay and discharge to a skilled nursing facility). Predictors did not vary substantially by time of readmission after discharge within the 30-day window.
Thirty-day readmissions after an AECOPD remain a major healthcare burden, and are characterized by a similar spectrum of readmission diagnoses. Predictors associated with readmission include both patient and clinical factors. Development of a COPD-specific risk stratification algorithm based on these factors may be necessary to better predict patients with AECOPD at high risk of early readmission.
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