The lung microbiome in children with HIV-bronchiectasis: A cross-sectional pilot study

Abstract

Background: Data on the lung microbiome in HIV-infected children is limited. The current study sought to determine the lung microbiome in HIV-associated bronchiectasis and to assess its association with pulmonary exacerbations. Methods: A cross-sectional pilot study of 22 children (68% male, mean age 10.8 years) with HIV-associated bronchiectasis and a control group of 5 children with cystic fibrosis (CF). Thirty-one samples were collected, with 11 during exacerbations. Sputum samples were processed with 16S rRNA pyrosequencing. Results: The average number of operational taxonomy units (OTUs) was 298±67 vs. 434±90, for HIV-bronchiectasis and CF, respectively. The relative abundance of Proteobacteria was higher in HIV-bronchiectasis (72.3%), with only 22.2% Firmicutes. There was no correlation between lung functions (FEV 1 % and FEF 25/75 %) and bacterial community (r=0.154; p=0.470 and r=0.178; p=0.403), respectively. Bacterial assemblage of exacerbation and non-exacerbation samples in HIV-bronchiectasis was not significantly different (ANOSIM, R HIV-bronchiectasis =0.08; p=0.14 and R CF =0.08, p=0.50). Higher within-community heterogeneity and lower evenness was associated with CF (Shannon-Weiner (H')=5.39±0.38 and Pielou's evenness (J) 0.79±0.10 vs. HIV-bronchiectasis (Shannon-Weiner (H')=4.45±0.49 and Pielou's (J) 0.89±0.03. Conclusion: The microbiome in children with HIV-associated bronchiectasis seems to be less rich, diverse and heterogeneous with predominance of Proteobacteria when compared to cystic fibrosis.