The vaginal microbiota of healthy pregnant women during their third trimester in Ismailia, Egypt

Maternal and neonatal health outcomes have proven to be primarily dependent on the vaginal microbiota during pregnancy. The aim of the current study was to characterize the vaginal microbiome of Egyptian pregnant women in Ismailia, during the third trimester using 16S rRNA next-generation sequencing of the V3 - V4 hypervariable region. The genera with the highest relative abundance were Lactobacillus, followed by Gardnerella, Prevotella, and Ureaplasma. Lactobacillus iners was the sole dominant Lactobacillus species. Alpha and beta diversity revealed no significant differences between vaginal microbial communities in respect to parity. LEfSe analysis identified no significant features when comparing primigravida and multigravida. Highly positive correlation pairs were detected between the genera Gardnerella and Ureaplasma. Other positive correlation cluster pairs included Staphylococcus-Streptococcus, and Staphylococcus-Corynebacterium, and Aerococcus-Atopobium. A large positive correlation polymicrobial cluster was detected between the genera Anaerococcus, Campylobacter, Corynebacterium, Dialister, Fingoldia, Mobiluncus, Peptoniphilus, Peptostreptococcus, Porphyromonas, Prevotella, Veillonella, and WAL_1855D. Urogenital vaginal pathogens may promote normal pregnancy rather than preterm birth under Lactobacillus-dominant vaginal microbial communities. Larger cohorts characterizing the vaginal microbiota in Egypt are warranted.