16S amplicon sequecing of homo sapiens: cervical swab
Genomic DNA was extracted from the collected samples using the CTAB method. The concentration of DNA was quantified using a Nanodrop spectrophotometer, and its purity and integrity were assessed via 1% agarose gel electrophoresis. Subsequently, the extracted DNA was diluted to a final concentration of 1 ng/l using sterile water. Amplification of the 16S rRNA genes was conducted with 341F/806R primers that incorporated barcodes for sample identification (Guo et al., 2017). PCR reactions were performed in 30 L volumes, comprising 15 L of High-Fidelity PCR Master Mix (New England Biolabs), 0.2 M of both forward and reverse primers, and approximately 10 ng of template DNA. The resulting amplicons were combined in equal proportions and purified using the TIANgel Purification Kit (TIANGEN Biotech). Sequencing libraries were then constructed utilizing the TIANSeq Fast DNA Library Prep Kit (Illumina) provided by TIANGEN Biotech. Library quality was assessed using the Qubit@ 2.0 Fluorometer (Thermo Scientific) and the Agilent Bioanalyzer 2100 system. Finally, the prepared library was sequenced on the Illumina platform, following the 2  250 bp paired-end sequencing protocol.