Respiratory microbiome profiles differ by recent hospitalization and nursing home residence in patients on mechanical ventilation

Abstract

Background Healthcare-associated pneumonia (HCAP) is a heterogeneous disease. We redefined nursing-home- and hospital-associated infections (NHAI) group by revising existing HCAP risk factors. The NHAI group comprised nursing home residents with a poor functional status, or recent (past 90 days) hospitalization or recent (past 180 days) antibiotic therapy. Our aim was to determine whether respiratory microbiota profiles are related to newly defined NHAI group in critically ill patients on mechanical ventilation. Methods The 180 endotracheal aspirates (ETAs) from 60 mechanically ventilated ICU patients (NHAI group, n = 24; non-NHAI group, n = 36) were prospectively collected on days 1, 3 and 7 in a university hospital. The bacterial community profiles of the ETAs were explored by 16S rRNA gene sequencing. A phylogenetic-tree-based microbiome association test (TMAT), generalized linear mixed models (GLMMs), the Wilcoxon test and the reference frame method were used to analyze the association between microbiome abundance and disease phenotype. Results The relative abundance of the genus Corynebacterium was significantly higher in the pneumonia than in the non-pneumonia group. The microbiome analysis revealed significantly lower α-diversity in the NHAI group than in the non-NHAI group. In the analysis of β-diversity, the structure of the microbiome also differed significantly between the two groups (weighted UniFrac distance, Adonis, p < 0.001). The abundance of Corynebacterium was significantly higher, and the relative abundances of Granulicatella, Staphylococcus, Streptococcus and Veillonella were significantly lower, in the NHAI group than in the non-NHAI group. Conclusions The microbiota signature of the ETAs distinguished between patients with and without risk factors for NHAI. The lung microbiome may serve as a therapeutic target for NHAI group.

Comparative study of bacterial flora in bronchoalveolar lavage fluid of pneumonia patients based on their pneumonia subtypes and comorbidities using 16S ribosomal RNA gene analysis

“…Our data showed that Corynebacterium species were the second most frequently detected bacterial species in patients with HAP (Table 2) and significantly frequently detected in patients with cerebrovascular diseases (Table 3). Corynebacteria usually cause pneumonia in elderly patients with impaired airway clearance and immunocompromised conditions [21]. Patients with cerebrovascular diseases were compatible with these clinical conditions.…”

Sepsis and the Human Microbiome. Just Another Kind of Organ Failure? A Review

“…Additionally, they demonstrated that ARDS had abundant Betaproteobacteria, Staphylococcus , Streptococcus , and Enterobacteriaceae, which may play a pivotal role in the pathophysiology of ARDS patients [ 13 ]. Patients who had nursing-home and hospital-associated infection (NHAI) pneumonia had significantly more reduced alpha diversity than non-NHAI pneumonia patients [ 15 ]. Cigarette smoking trauma patients are more likely to suffer from an ARDS.…”

“…The individual’s lifestyle and comorbidities also appear to be relevant factors in the composition of an individual microbiome. For example, age influences the composition of the microbiome during pneumonia; thus, elderly patients suffering from nursing-home- or hospital-acquired infection also appear to have reduced alpha diversity [ 15 ]. Patients older than 75 years have a significantly higher number of Streptococcus phylotypes than those aged 74 years and younger [ 48 ].…”

Translocation and Dissemination of Gut Bacteria after Severe Traumatic Brain Injury

“…Hence, the evaluated richness and diversity of the lung microbiome may suggest an imbalanced lung milieu. The extent of the similarity between microbial communities based on the degree of structural overlap was characterized by beta diversity (inter-sample diversity) [ 33 ]. The repeatability of samples in each group was determined to be good based on PCoA analysis, and the difference between lung samples was significant.…”