NICU Fellow Nationwide Children's Hospital Columbus, Ohio, United States
Background: Research on the airway microbiome in premature infants remains limited, with published studies evaluating infants early on for the development of bronchopulmonary dysplasia (BPD). However, there is a need for studies which examine the airway microbiome in these infants after they are diagnosed with BPD. We postulate that airway microbiome profiles may identify disease progression trajectories in established BPD. Objective: To evaluate the airway microbiome of patients with BPD and examine potential correlations between bacterial profiles and clinical factors such as need for prolonged mechanical ventilation. Design/Methods: Tracheal aspirates (TA) were collected from 16 patients with BPD. Oropharyngeal (OP) and nasopharyngeal (NP) swabs were co-collected in 7 of these patients. DNA isolation and amplification to target the V3-4 hypervariable region of the 16S rRNA gene was done and the sequenced PCR amplicons were analyzed. Clinical data was collected. The 16 patients were divided into two equal groups based upon days on invasive mechanical ventilation: group 1 (shortened, < median) and group 2 (prolonged, > median). Results: The median gestational age was 25 weeks and 5 days (IQR 24w3d to 26w6d), with a median birth weight of 673 grams (IQR 582- 862). The median length of mechanical ventilation in these patients was 84 days (IQR 60 – 169, p= 0.001). The microbiome of those in the prolonged group had a median of 69% Proteobacteria (IQR 60 – 75%) and 0% Actinobacteria (IQR 0 – 15%) while those in the shorter group had a median of 26% Proteobacteria (IQR 22 – 48%) (p=0.007) and 13% Actinobacteria (IQR 4 – 32%) (p= 0.038). The median length of stay was prolonged in the prolonged ventilation group at 232 days (IQR 149-288) vs. 139 days (IQR 117-150) (p < 0.001). There was no difference when looking at birth weight or gestational age. Additionally, profiles differed in the separate niches with Proteobacteria predominating in the TA samples, Firmicutes in the OP, and Actinobacteria in the NP samples.
Conclusion(s): Our findings suggest that an abundance of Proteobacteria in the TA at 36 weeks PMA may predict patients with BPD who require prolonged mechanical ventilation. Specifically, those who had a profile showing increased relative abundances of Proteobacteria and decreased relative abundances of Actinobacteria required prolonged mechanical ventilation compared to their peers. Although our sample size is limited, it merits further study to determine if the airway microbiome, or even specific bacterial communities, may serve as potential biomarkers to predict clinical severity in infants with established BPD.
.jpg)
.jpg)