Deciphering the Relationships between the Fungal and Bacterial Assemblages and their Activities in the Indoor Residential Environments

Residential home is a key indoor built environment for citizens in developed countries. Withinresidences, occupants are constantly exposed to different types of biological matters includingbacteria, fungi, viruses and parasites through contact and inhalation. Occupants themselves arealso part of the indoor built environment ecosystem as microorganisms associated with humansare frequently released into the indoor spaces. A comprehensive understanding of the microbiallife in residences has significant health implications to ensure the comfort and well-being of theoccupants. Traditionally, culture-dependent methods are used to query the microorganismspresent in the indoor environments. However, since cultivation cannot capture the breadth ofmicrobial diversity in an environment, high-throughput next-generation sequencing technologyhas been widely adopted in recent years to investigate the complex microbial communities thatare present in indoor environments and on occupants. A number of studies have illustrated thebacteria and fungi that are present within homes in Western countries, but since the livingconditions, lifestyles and occupants in different geographical locations are intrinsically different,our understanding of the microbiology in non-Western homes is lacking.In order to establish an in-depth view of the microbiology in residences in Hong Kong (one ofthe world’s most densely populated cities), we propose an innovative research plan in this studythat makes use of advanced sequencing methods to analyze the fungi and bacteria that are presentin air and on object surfaces of residential homes as well as associated with occupants over fourseasons. In addition to only identifying the bacteria and fungi that are merely present in the totalmicrobial communities through DNA analysis, the microbial members that are metabolicallyactive will also be determined and quantified through RNA analysis. Furthermore, thecorrelations within and between the bacterial and fungal members in the total and activecommunities will be queried by computational network and correlational analyses to determinethe co-abundance and co-exclusion relationships. Overall, our goal is to integrate the bacterialand fungal results over seasonal timescale to establish a complete understanding of the microbiallife that occupants in residences of Hong Kong are exposed to, so that the appropriate measuresand building designs can be implemented in the indoor environments to best ensure the health ofoccupants.