Nasal sampling methods for the Microbiome: What is out there to find out what is in there. Nasal microbiome

There is currently no consensus on the optimal sampling strategy for the study of the human nasal microbiome. Thus, we conducted a cross-sectional study to compare three commonly used non-invasive techniques for investigation sampling of the sinonasal microbiome of the middle meatus: nasosorptions (NS) for collection of mucosal fluids, nasal swabs (SW), and nasal lavage (NL) with saline solution. We included 18 healthy non-smoking adult volunteers without acute or chronic nasal diseases, absence of current antibiotic use, and a negative COVID-19 test. Microbial DNA was extracted using a kit designed for samples containing high proportions of eukaryotic host material like nasal mucosa. After extraction, DNA yield was quantified, and the abundance and composition of microorganisms was analyzed applying 16S rRNA gene-targeted droplet digital PCR (ddPCR) and amplicon sequencing. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-2201-05.