The first group of ‘normal flora’ was characterized by the predominance of AZ 628 solubility dmso a combination of four Lactobacillus species excluding L. gasseri, whereas in the second

group L. gasseri and L. vaginalis predominated. The third group, associated with BV, was dominated by A. vaginae, G. vaginalis, and L. iners. Group 1 in our study was similar to community groups I, III, and V as defined by Ravel et al.; group 2 corresponded to community group II, and group 3 was similar to community group IV [14]. All 3 microbiome groups were represented in the different groups of women (HP, CP without BV, and CP with BV). However, among the women without BV there appeared to be large differences in the relative distribution of the different LCA groups according to ethnicity. Caucasian women mostly belonged to group 1 or 2, while African/Asian women mostly belonged to group 3. We should therefore not assume that all SBI-0206965 nmr microbiomes with low Nugent scores are similar. Our data are in line with the findings of Ravel et al., who reported that healthy African/Asian women have a higher probability of belonging to group 3, the ‘BV type flora’ group [16, 26]. The results of this study are in line with published

literature showing that L. crispatus is consistently present with high counts of >108 copies/mL in a healthy vaginal ecosystem as defined by the Nugent score (0–3) whereas G. vaginalis and A. vaginae are highly present in women with BV [11, 24]. We explored the correlation of specific species

with the individual Nugent scores and showed that L. vaginalis (R = −0.421) shows the same inverse correlation as L. crispatus (R = −0.411) with increasing Nugent scores. A low correlation was seen for L. gasseri and the Nugent score and this may reflect the confounding effect of ethnicity. This study is among the first to show that L. vaginalis is highly represented in the normal healthy vaginal flora with typical counts of 106 copies/mL. L. crispatus, L. jensenii, L. gasseri, and L. vaginalis were less frequently present in women at higher risk of an STI, while L. iners remained present. The fact that L. iners is always present, even when A. vaginae and G. vaginalis Calpain are present, makes us wonder whether L. iners increases susceptibility to BV. This would be in line with the findings of Antonio et al. who recently demonstrated that only L. crispatus had a protective effect against acquisition of BV [27]. We observed higher bacterial counts with the combined lysis-Boom extraction compared to the Boom extraction alone (results not shown). The extra lysis step particularly improved the efficiency of the DNA extraction from Gram positive microorganisms. As a result of these different methods of extraction, we were unable to directly compare the quantitative counts from the HP and CP group (Figure 3) and this represents a weakness of this study.