Trial lecture title: Current knowledge on environmental microbial exposure in early life and the development of asthma and allergy.
Th ordinary opponents are:
- First opponent: Senior researcher Martin Taübel, National Institute for Health and Welfare, Finland
- Second opponent: Professor Maria Jenmalm, Linkoping University, Sweden
- Leader of the committee: Associate Professor Yuri Kiselev, OsloMet, Norway
The leader of the public defence is Professor Kjell Sverre Pettersen, OsloMet.
The main supervisor is Professor Colin Charnock, OsloMet. The co-supervisor is Professor Oddbjørn Sjøvold, NTNU.
Thesis abstract
People spend much of the day indoors. Here they are exposed to the microorganisms that are present in buildings, often referred to as the indoor microbiome. This contact is now known to have relevance for human health and development.
The aim of this thesis was to provide new insights into the structure and significance of indoor microbiomes in Norwegian kindergartens and nursing homes, based on modern high-throughput sequencing (HTS) and supplementary analyses.
HTS-technologies are enabling unprecedented insights into microbial communities.
Materials and methods
Analyses was performed on ventilation filter dust and floor dust samples collected from Norwegian kindergartens and nursing homes.
Dust samples were analyzed for microbial content by sequencing 16S rRNA gene amplicons on several HTS-platforms.
In addition, dust samples were analyzed using supplementary culture-, endotoxin-, and antibiotic resistance genes (ARG)-analyses.
Results
It was found that ventilation exhaust-filter dust and indoor floor dust samples had high proportions of human-associated bacterial taxa, some of clinical significance, such as Propionibacterium, Streptococcus, Staphylococcus, and Corynebacterium.
In addition, the results of culture-, endotoxin-, and ARG-analyses provided valuable information to supplement the results generated by HTS.
Further, it was found that for classification of indoor microbial communities, the Oxford Nanopore Technologies (ONT) MinION was able to provide greater taxonomic resolution than Illumina MiSeq, particularly at the species level.
Conclusions
The works presented in this thesis taken together, show that indoor microbial communities in kindergartens and nursing homes as revealed by the HTS-approach, are clearly structured by human occupancy.
Furthermore, the newest addition to the HTS-market, the ONT MinION sequencing platform, provided good taxonomic assignments, by comparison with the Illumina MiSeq platform.
This suggests a potential for future use of ONT MinION for studies of indoor microbial communities.
