title: 16S rRNA sequencing of the vaginal microbiome of pregnant women
design: Vaginal swab samples from 155 Caucasian women who were classified as either term (38+0/7 wks, n=107) or preterm (<37+0/7 wks, n=48) in exclusion of any other medical or obstetric complications. The vaginal microbiomes of these women were characterized by 16S rRNA sequencing using a universal set of Illumina adapter containing primers: 341F (5- TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGCCTACGGGNGGCWGCAG-3) and 805R (5- GTCTCGTGGGCTCGGAGATGTGTATAAGAGACAGGACTACHVGGGTATCTAATCC-3). For the preparation of libraries, we used the standardized 16S Metagenomic Sequencing Library Preparation Protocol (Illumina), using KAPA HiFi HotStart ReadyMix 2X for amplification. The amplicons of each sample were labeled with Nextera XT Indexes. Libraries of pooled samples were sequenced on the Illumina MiSeq sequencer in the 2x300 bp pair-end runs (MiSeq Reagent kit v3).