CORRELATION OF ENVIRONMENTAL MICROBIAL DIVERSITY WITH AIRWAY DISEASE IN REFRACTORY ASTHMA

Abstract

TYPE: Abstract Publication TOPIC: Allergy and Airway PURPOSE: The influence of subacute bacterial infection in refractory asthma remains elusive. Bacterial dysbiosis and potentially environmental microbe exposures contribute to disease in asthma. We hypothesize that biodiversity within home environments influences airway microbiome and control of disease in refractory asthma. METHODS: We examined the microbiome of bronchoalveolar lavage (BAL) samples and home dust specimens of 5 refractory asthmatics, at time points 12 months apart. A custom, aggressive genomic DNA extraction was used to obtain a more diverse composition of microbial DNA. Bacterial 16S rDNA (V4-V5) was amplified, packaged into libraries, and sequenced in a multiplex manner using 2X300bp Illumina chemistry. Sequences were processed and profiled using QIIME2. Clinical parameters collected include BAL cell count differential, cultures, Asthma Control Test (ACT) and FEV1. RESULTS: Two subjects had positive BAL cultures, one with rare Pseudomonas and another with Mycobacterium. Follow-up bronchoscopy showed culture resolution and reduced airway neutrophilia after directed treatment. Subjects with clinical improvement (3 of 5) trended toward a significant increase in BAL biodiversity by genus (p=0.065, two-tailed T-test), and reduced environmental microbial DNA at month 12. Subjects without clinical improvement of asthma (2 of 5) demonstrated predominant pathogenic bacterial DNA and negative BAL cultures, therefore untreated clinically. CONCLUSIONS: Preliminary analysis of environmental and airway microbiome suggests asthma control is dependent on treatment of clinical and sub-clinical microbes. Higher airway and lower environmental biodiversity may correlate with improved asthma control. CLINICAL IMPLICATIONS: Our research shows clinical cultures are sub-optimal in identifying bacterial species in the lower airways. DISCLOSURE: No significant relationships. KEYWORDS: airway microbiome, refractory asthma