The maternal microbiota.
As expected, there were no differences in the maternal vaginal microbiota (prior to randomization) in terms of bacterial DNA load (measured by quantitative PCR [qPCR]) or alpha diversity, when comparing mothers from the vaginal-seeding versus control groups (Differences in bacterial DNA load and composition between treatment groups at differing body sites, collection types, and times. (A) Bacterial DNA load in maternal vaginal swabs (both inoculated with vaginal fluids), gauze (control gauze not inoculated with vaginal fluids), infant skin (forearm), and infant stool. (B) Bacterial load of the 20 most abundant genera in gauzes from the two groups. Samples and taxa are ordered by unsupervised hierarchical clustering based on bacteria load. Bacterial load was estimated by 16S rRNA gene copy number based on qPCR using 16S rRNA gene universal primers. Wilcoxon signed-rank tests were performed for intergroup comparisons, with statistical significance indicated as follows: *, Shannon diversity index by treatment group at differing body sites, collection types, and times. Shannon diversity index values were estimated using the R package DivNet and assessed for significance using the function “betta” from the R package breakaway. Intergroup comparisons were considered statistically significant and were indicated as follows: *, 