Sample collection, processing, and sequencing
Vaginal samples were collected with REMEL ESwabs. Vaginal swabs were
placed into the sterile tube then stored at −80°C until DNA extraction.
Frozen vaginal swabs were immersed in sterile PBS then DNA extraction
was performed using the Qiagen DNeasy PowerSoil Kit (Qiagen, Hilden,
Germany), as described by the manufacturer. DNA concentration was
quantified by Qubit (ThermoFisher Scientific, Waltham MA).
Library preparation was performed using QIAseq 16S/ITS Panel Kit
(Qiagen, Hilden, Germany) for sequencing the V1–V9 region of the 16S
rRNA genebacterial gene. Library quantification was done using QIAseq
Library Quant Assay (Qiagen, Hilden, Germany) kit following the
manufacturer’s instructions with Applied Biosystems QuantStudio 7 Flex
Real-Time PCR (Applied Biosystems Inc., Foster City, California).
Sequencing was performed with the Illumina MiSeq platform using the
MiSeq v3 Reagent Kit (Illumina, San Diego, CA, United States).