NMR Metabolomics of Symbioses Between Bacterial Vaginosis Associated Bacteria Original paper

What was studied?

This study investigated the metabolic interactions and symbiotic relationships between bacterial vaginosis (BV)-associated bacteria, particularly Gardnerella vaginalis and Prevotella bivia, using NMR metabolomics. It aimed to characterize their metabolic strategies, assess how co-culture influences metabolite production, and explore implications for vaginal microbiome composition and related health outcomes​.

Who was studied?

The study focused on a panel of BV-associated bacterial isolates, including G. vaginalis (multiple strains), P. bivia, Atopobium vaginae, Mobiluncus curtisii, and Peptostreptococcus anaerobius, along with a selection of Lactobacillus species, which are commonly associated with vaginal health​.

Most Important Findings

The study revealed that P. bivia and G. vaginalis exhibit a mutualistic metabolic relationship, with G. vaginalis supplying asparagine and P. bivia providing uracil. This metabolic exchange influences their ability to thrive in the vaginal environment, potentially promoting BV. The metabolic diversity within G. vaginalis was highlighted, distinguishing strains using either the bifid shunt (BS) pathway or mixed acid fermentation (MAF). Notably, MAF strains produced acetate, formate, and ethanol, contributing to alterations in the vaginal chemical environment. The co-culture of P. bivia with MAF G. vaginalis strains increased acetate production, a hallmark metabolite associated with BV and spontaneous preterm birth (sPTB)​.

Additionally, the study confirmed that L. iners cannot produce acetate, meaning that acetate detected in L. iners-dominated microbiomes originates from other BV-associated bacteria like G. vaginalis. This suggests that acetate levels may serve as a microbial marker for vaginal dysbiosis and potential inflammatory conditions. The findings reinforce that lactate production by Lactobacillus species, particularly L. acidophilus, plays a protective role by acidifying the vaginal environment, whereas acetate and succinate contribute to BV-related dysbiosis​.

Implications of this study

This study provides insights into how bacterial interactions shape the vaginal microbiome and contribute to BV and sPTB. The findings suggest that variations in G. vaginalis metabolism influence the severity and persistence of BV, affecting vaginal pH and inflammatory responses. The identification of key metabolic interactions could refine prediction models for BV and sPTB by incorporating metabolite-based biomarkers like acetate, aspartate, and lactate. Clinicians could leverage this information to develop targeted interventions, such as probiotic therapies, to restore a lactate-dominant vaginal microbiome and reduce the risk of adverse reproductive outcomes​.