Comparison of the mycobiome of the homes and respiratory secretions of patients with chronic pulmonary aspergillosis

Abstract

Indoor environments, such as homes, contain a variety of microbial communities, with airborne fungi serving as a significant source of indoor micobiome associated with numerous fungal diseases. House dust serves as a valuable matrix for microbial analysis, functioning as a long-term reservoir for airborne fungal spores and representing the microbiological history of patients' homes. Inhalation of mould is linked to respiratory health problems, as the mucus in the respiratory tract creates an environment suitable to fungal growth.Thus, studying the microbial community in household dust is crucial for understanding its impact on human respiratory health. The rapid progress in DNA sequencing technology has intensified research into the relationships between human-associated fungal diversity and that found in house dust within indoor environments. This study aims to compare the diversity of environmental and pathogenic fungi in house dust with environmental and allergenic fungi in sputum samples from patients with chronic pulmonary aspergillosis (CPA). Microbial populations in household dust of individuals with fungal infections were assayed by culture as well as by Next Generation Illumina MiSeq sequencing. The ITS1 and β-tubulin gene regions were targeted to characterise the fungal communities in dust and sputum samples. The sequence data generated via Illumina MiSeq were processed using QIIME v1.8 software which provided useful information about the fungal communities represented in each sample, with statistical tools to evaluate microbial diversity through alpha and beta diversity metrics. NGS microbiome analysis has been successful in identifying unknown or hard to culture fungi in indoor environments, with a particular abundance of xerophilic species detected through ITS and β-tubulin sequencing. Among these, Aspergillus penicillioides and Aspergillus candidus, known to produce allergens, were commonly found and are implicated in the development of allergic diseases.Our findings indicate that fungal diversity in dust samples was significantly higher than in sputum samples, suggesting that sputum acts as a selective environment, potentially excluding fungi that unable to grow at higher moisture and temperature conditions than those typical for household dust. This study contributes to our understanding of how indoor fungal communities intersect with human respiratory health and highlights the selective nature of respiratory environments for fungal survival.