Longitudinal Study of Pulmonary Microbial Dynamics in Lung Transplant Recipients with and without Bronchiolitis Obliterans Syndrome

Purpose The development of Bronchiolitis Obliterans Syndrome (BOS) has been previously linked to microbial pathogens within the transplanted lung. With advanced molecular technology, we are now able to further define microbial communities within the transplanted lung. We hypothesized that these microbial communities will be distinct in lung transplant recipients who develop BOS compared to those who remain stable. Methods and Materials Eighteen lung transplant recipients were included in this analysis. Nine patients developed BOS within 2 years. Bronchoscopy with bronchoalveolar lavage (BAL) was performed at 1, 3, 6, and 12 months post transplant. Bacterial 16S rDNA extracted from the BAL fluid was amplified using barcoded primers and PCR products were pooled and sequenced using 454 pyrosequencing. All the sequence reads were denoised and clustered into similar operational taxonomic units. Taxonomy annotation was assigned according to Ribosomal Database Project. Results The bacterial community of transplanted lungs was taxonomically diversified and consisted of micro-organisms belonging to 14 phyla. Inter-individual variation of the microbial community was greater than intra-individual variation for all patients. There was a distinct difference in the microbial community at the phylum and class taxonomic level between BOS and non-BOS patients (p Conclusions The pulmonary microbiota in lung transplant recipients is taxonomically diverse and dynamic over time and is distinct in patients who develop early BOS compared to those who remain stable. Our findings provide novel approaches to address the relationship between microbial communities and BOS development after lung transplantation.