Background Bacterial vaginosis (BV) is a vaginal disorder characterized by a depletion of the normal lactobacillus-dominant microbiota and overgrowth of mainly anaerobic bacteria. Objectives The study aimed to evaluate the distribution and abundance of the Gardnerella vaginalis clades and sialidase A gene in vaginal samples from Russian women, and investigate if the G. vaginalis sialidase A gene count detects an abnormal vaginal microbiota characteristic of BV more accurately than G. vaginalis load. Methods Vaginal samples from 299 non-pregnant patients of gynecological clinics were examined using Nugent scores and G. vaginalis clade and sialidase A gene quantitative real-time polymerase chain reactions (PCRs). Discriminatory power for BV microbiota was evaluated with receiver operating characteristic (ROC) analysis. Results The vaginal microbiota was characterized by Nugent scores as normal, intermediate, and BV microbiota in 162, 58, and 79 women, respectively. G. vaginalis clades 1, 2, 3, 4, and the sialidase A gene were detected in 56% (51–62%), 40% (34–45%), 20% (16–25%), 94% (91–96%), and 70% (64–75%) of vaginal samples, respectively. The frequency and abundance of clades 1, 2, 4, and the sialidase A gene as well as clade multiplicity were significantly associated with abnormal microbiota. The sialidase A gene was present in all multi-clade samples, in all single-clade samples comprising clades 1, 2, and 3, and in four of 84 (5% [2–12%]) samples comprising clade 4 only. Total G. vaginalis load showed significantly higher discriminatory power for abnormal microbiota than sialidase A gene count (areas under ROC curves 0.933 vs. 0.881; p = 0.0306). Conclusions Quantifying all four G. vaginalis clades discriminates between BV microbiota and normal microbiota more accurately than measuring G. vaginalis sialidase A gene. Clade 4 is strongly associated with BV microbiota, despite most clade 4 strains lacking the sialidase A gene.

According to the reference methods, C. trachomatis NAATs developed and used in Russia have relatively good performance characteristics for both invasive and non-invasive samples. However, larger studies that include symptomatic and asymptomatic patients as well as genital and extra-genital samples, and in comparison with other internationally well-recognized, validated, and ideally Food and Drug Administration-approved C. trachomatis NAATs performed strictly according to the manufacturer's instructions, need to be conducted.

The large majority of studies investigating associations between bacterial vaginosis (BV) and sexually transmitted infections (STIs) have been conducted among predominantly young women with high risk for STIs. Since a risky sexual behavior is a significant risk factor for both STIs and BV, this creates a bias toward an increased association between BV and STIs. This study evaluated associations between BV-associated vaginal microbiota and STIs (Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, and Neisseria gonorrhoeae) in a population of women with low risk for STIs and investigated STI outcomes depending on the dominating Lactobacillus species. Repository cervicovaginal samples collected from reproductive-age women from January 2014 to February 2019 were characterized for vaginal microbiota types and the STIs using multiplex real-time PCR assays. In total, 95 STI-positive and 91 STI-negative samples were included. A significant, age-independent association between BV-associated vaginal microbiota and the presence of C. trachomatis, M. genitalium, and T. vaginalis infections was identified (age-adjusted odds ratios 2.92 [95% confidence interval (CI) 1.24-7.03], 2.88 [95% CI 1.19-7.16], and 9.75 × 10 7 [95% CI 13.03-∞], respectively). Normal vaginal microbiota dominated by Lactobacillus crispatus, L. gasseri, or L. jensenii was a strong protective factor against C. trachomatis and/or M. genitalium infections, whereas L. iners-dominated microbiota was not significantly associated with C. trachomatis and/or M. genitalium positivity. The results of the present study confirm that STI prevention strategies should include interventions that also reduce the incidence of BV and promote a protective vaginal microbiota in both high-and low-risk women.

Introduction. Bacterial vaginosis (BV) is the primary cause of pathological vaginal discharge in women of reproductive age. Gardnerella vaginalis and Atopobium vaginae are considered key components of the vaginal microflora in BV. Etiology, pathogenesis and modes of transmission of BV are actively studied, however these questions still remain unanswered. Objective: investigate predictor factors of BV in women with vaginal discharge. Material and methods. In total, 318 women were included. As clinical material, vaginal samples were used. BV was diagnosed using the Nugent method. For quantitative determination of G. vaginalis and A. vaginae DNA, real-time PCR was used. Behavioral and anamnestic data were obtained from questionnaire filled out by the patients. Results. BV was diagnosed in 27 % of women. G. vaginalis and A. vaginae DNA was detected, respectively, in 93 % and 83 % of patients with BV, 73 % and 59 % - with intermediate microflora, 52 % and 38 % - with normal microflora. Difference between the three types of microflora in the frequency and concentrations of these microorganisms were statistically significant. Detection of G. vaginalis and A. vaginae were significant predictor factors of BV (OR 12.2; 95 % CI 5.1-29.4 and OR 7.9; 95 % CI 4.2-14.9, respectively), with chances to diagnose BV being manifold increased when clinically significant concentrations of these bacteria were detected (≥3×106 and ≥8×105 DNA copies/ml for G. vaginalis and A. vaginae, respectively). Detection of clue cells in Gram stained preparations was shown to be the strongest BV predictor (OR 765.6; 95 % CI 99.6-5883.2). Conclusions. BV is diagnosed in more than one fourth of women with vaginal discharge. Detection of G. vaginalis and A. vaginae, especially in clinically significant concentrations, and clue cells in Gram stained preparations are significant predictor factors of BV.