The pulmonary microbiome in non-cystic fibrosis bronchiectasis

Introduction: Pulmonary microbiome composition can predict future exacerbations in bronchiectasis (Rogers G.B., et al. Ann Am Thorac Soc. 2014). To date, most data in this field is derived from Caucasian populations and focuses primarily on the bacterial component of the microbiome (the bacteriome). Consequently little data is available in Asian cohorts, and the fungal component of the microbiome (the mycobiome) is infrequently reported (Chotirmall S., et al. Respirology. 2017). Methods: We prospectively recruited n=59 patients with stable bronchiectasis at three separate clinical sites across Singapore. To determine the bacteriome and mycobiome in patient sputum, we performed shotgun sequencing of 16S rRNA and 18S ITS amplicons respectively. We investigated the correlation between observed microbiome architecture and clinical disease markers in our cohort. Results: Microbiome analysis of our Asian cohort revealed a distinct microbiome in bronchiectasis. The Asian bacteriome was dominated by taxa belonging to Streptococcus , Haemophilus and Pseudomonas species. The bronchiectatic mycobiome was characterised by the predominance of Candida spp. Aspergillus fumigatus and Saccharomyces cerevisiae . Conclusion: Our findings represent the first characterisation of the Asian pulmonary microbiome in bronchiectasis, including analysis of the bacterial and fungal microbiota. The direct and mechanistic implications of these findings on clinical disease, in comparison to Caucasian cohorts, require further investigation. Funding: This research is supported by the Singapore Ministry of Health’s National Medical Research Council under its Transition Award (NMRC/TA/0048/2016) (S.H.C).