Vaginal microbiota composition affects many facets of reproductive health. Lactobacillus inersdominant microbial communities are associated with poorer outcomes, including higher risk of bacterial vaginosis (BV), compared with vaginal microbiota rich in Lactobacillus crispatus.Unfortunately, standard-of-care metronidazole therapy for BV typically results in dominance of L. iners, likely contributing to post-treatment relapse. Here we generate an L. iners isolate collection comprising 34 previously unreported isolates from 14 South African with and without BV and 4 previously unreported isolates from 3 US women and we report an associated genome catalog comprising 1,218 vaginal Lactobacillus isolate genomes and metagenome-assembled genomes (MAGs) from >300 women across four continents. We show that, unlike L. crispatus, L. iners growth is dependent on L-cysteine in vitro and we trace this phenotype to the absence of canonical cysteine biosynthesis pathways and a restricted repertoire of cysteine-related transport mechanisms. We further show cysteine concentrations in cervicovaginal lavage samples correlate with Lactobacillus abundance in vivo and that cystine uptake inhibitors selectively inhibit L. iners growth in vitro. Combining an inhibitor with metronidazole promotes L. crispatus dominance of defined BV-like communities in vitro by suppressing L. iners growth. Our findings enable a better understanding of L. iners biology and suggest candidate treatments to modulate the vaginal microbiota to improve reproductive health for women globally.

Half of postmenopausal women experience genitourinary syndrome of menopause, for which many use lubricating vaginal products. The effect of vaginal products on uropathogenic and commensal vaginal bacteria is poorly understood. We evaluated the effect of five common vaginal products (KY Jelly, Replens Silky Smooth lubricant, coconut oil, Replens Long-Lasting moisturizer or Trimo-San) on growth and viability of Escherichia coli and Lactobacillus crispatus. Bacteria were co-cultured products alone and in the presence of both vaginal epithelial cells and selected products. Bacterial growth was compared between conditions using an unpaired t-test or ANOVA, as appropriate. All products except for coconut oil significantly inhibited growth of laboratory and clinical strains of Escherichia coli (p < 0.02). Only two products (Replens Long-Lasting moisturizer and Trimo-San) significantly inhibited growth of Lactobacillus crispatus (p < 0.01), while the product Replens Silky Smooth stimulated growth (p < 0.01). Co-culture of selected products in the presence of vaginal epithelial cells eliminated the inhibitory effects of the products on E. coli. In conclusion, in vitro exposure to vaginal moisturizing and lubricating products inhibited growth of Escherichia coli, though the inhibition was mitigated by the presence of vaginal epithelial cells. Lactobacillus crispatus demonstrated less growth inhibition than Escherichia coli. Urinary tract infections (UTIs) are among the five most commonly diagnosed problems in the ambulatory urologic setting, and over 80% occur in women 1. Up to 70% of women will experience at least one UTI in their lifetime, and one third to one half will experience a recurrence 2. An estimated 10% of women over 60 are diagnosed with recurrent UTIs (rUTI), which are becoming increasingly difficult to treat as antibiotic resistance limits therapeutic and preventive options 3,4. Over 80% of community-acquired UTIs are caused by Escherichia coli 5 , and recurrent UTIs are strongly linked to vaginal E. coli colonization 6. Lactobacillus spp. dominance of the vaginal microbiota is an important factor in maintaining urogenital health. Decreased vaginal Lactobacillus spp. colonization is associated with increased UTI risk, and a lack of hydrogen peroxide (H 2 O 2)-producing lactobacilli has been associated with vaginal E. coli colonization in women with rUTI 7,8. While H 2 O 2 is no longer thought to be the mechanism of beneficial effects, the ability to produce H 2 O 2 in vitro is a marker of species (e.g. L. crispatus) and strains that are more likely to be beneficial than non-producing species and strains (e.g. L. iners). A vaginal L. crispatus probiotic was found to reduce recurrent UTI in women who established high quantity colonization 9 , indicating a benefit of vaginal colonization with Lactobacillus spp. in women with recurrent UTIs. The use of over-the-counter vaginal lubricants and moisturizers for vulvovaginal dryness or sexual activity is common, especially among postmenopausal women 10. These produc...

Vaginal microbiota composition affects several important reproductive health outcomes. Lactobacillus crispatus-dominant bacterial communities have favorable associations whereas anaerobe-dominant communities deficient of lactobacilli are linked to poor outcomes, including bacterial vaginosis (BV). Lactobacillus iners, the most abundant vaginal species worldwide, has adverse associations compared to L. crispatus, but standard metronidazole treatment for BV promotes L. iners-dominance, likely contributing to post-treatment relapse. L. iners is under-studied because it fails to grow in standard Lactobacillus media in vitro. Here we trace this in vitro phenotype to a species-specific cysteine requirement associated with limitations in cysteine-related transport mechanisms and show that vaginal cysteine concentrations correlate with Lactobacillus abundance in vivo. We demonstrate that cystine uptake inhibitors selectively impede L. iners growth and that combining an inhibitor with metronidazole thus promotes L. crispatus dominance of defined BV-like communities. These findings identify a novel target for therapeutic vaginal microbiota modulation to improve reproductive health.

The objective of this study is to assess the cost-effectiveness of three different strategies with different availabilities of cesarean sections (CS). The setting was rural and urban areas of India with varying rates of CS and access to comprehensive emergency obstetric care (CEmOC) for women of reproductive age in India. Three strategies with different access to CEmOC and CS rates were evaluated: (A) India’s national average (50.2% access, 17.2% CS rate), (B) rural areas (47.2% access, 12.8% CS rate) and(C) urban areas (55.7% access, 28.2% CS rate). We performed a first-order Monte Carlo simulation using a 1-year cycle time and 34-year time horizon. All inputs were derived from literature. A societal perspective was utilized with a willingness-to-pay threshold of $1,940. The outcome measures were costs and quality-adjusted life years were used to calculate the incremental cost-effectiveness ratio (ICER). Maternal and neonatal outcomes were calculated. Strategy C with the highest access to CEmOC despite the highest CS rate was cost-effective, with an ICER of 354.90. Two-way sensitivity analysis demonstrated this was driven by increased access to CEmOC. The highest CS rate strategy had the highest number of previa, accreta and ICU admissions. The strategy with the lowest access to CEmOC had the highest number of fistulae, uterine rupture, and stillbirths. In conclusion, morbidity and mortality result from lack of access to CEmOC and overuse of CS. While interventions are needed to address both, increasing access to surgical obstetric care drives cost-effectiveness and is paramount to optimize outcomes.