Taxonomic profiling of EBC samples
The 16S-based microbiome taxonomic profile of the microbial EVs isolated from the participants’ EBC samples was analyzed using MDx-Pro ver. 2 (MD Healthcare, Korea) as described previously 14. In summary, after trimming and merging the paired-end reads, only sequence reads with lengths greater than 350 bp and below 550 bp were used for further analysis. Operational taxonomic units (OTUs) were assigned using VSEARCH de novo clustering at the genus level with a similarity threshold of 97%. The Silva 132 sequence database was used for taxonomic assignment of the OTUs in all samples.