Figure 1. Variability of vaginal bacteria in women without BV.

The line graphs show the changes in vaginal bacteria measured as 16S rRNA gene copies per swab in a participant exhibiting a stable bacterial biota (A) and another with dynamic patterns (B). The red line indicates menses. Clinical diagnosis was performed using Amsel's criteria (green box in upper graph indicating negative for BV). Gram staining using the Nugent criteria (the score is indicated as a number from 0–10 in the box) was also performed. A score of 0–3 indicates negative for BV, 4–6 reflects intermediate BV flora and 7–10 denotes positive for BV. Levels of the human 18S rRNA gene (red circles) were used to assess the amount of vaginal fluid loaded on each swab as reflected by human cell content. BVAB denotes bacterial vaginosis associated bacterium.