Overview

Probiotic therapy offers a promising microbiome-targeted intervention (MBTI) for bacterial vaginosis (BV) by addressing the condition’s microbial dysbiosis characteristic and the host’s inflammatory response. In BV, the vaginal microbiota shifts from a community dominated by Lactobacillus to an overgrowth of anaerobic species such as Gardnerella vaginalis, Prevotella, Mobiluncus, and Atopobium vaginae.^[1] This dysbiosis disrupts the protective acidic environment of the vagina, facilitates pathogenic colonization, and triggers local inflammation. Probiotic interventions not only reverse this microbial imbalance but also demonstrate beneficial effects on host immunity, recurrence rates, and overall treatment outcomes. These effects substantiate probiotics as valid MBTIs and reinforce the diagnostic accuracy of the BV-associated microbiome signature.

Validation of Probiotics as an MBTI

The use of probiotics such as Lactobacillus crispatus and Saccharomyces cerevisiae in BV treatment is supported by both mechanistic and clinical evidence. Lactobacillus crispatus plays a pivotal role in restoring vaginal health by producing lactic acid, hydrogen peroxide, and bacteriocins—metabolites that inhibit the growth of key BV-associated pathogens, including Gardnerella vaginalis and Neisseria gonorrhoeae. In vitro studies confirm that L. crispatus not only suppresses pathogen proliferation but also maintains compatibility with the host’s mucosal environment, enhancing epithelial barrier function and promoting recolonization by beneficial flora. Additionally, L. crispatus demonstrates the capacity to adhere to epithelial surfaces, effectively outcompeting harmful anaerobes for space and resources.^[2]

Similarly, Saccharomyces cerevisiae has emerged as a novel probiotic candidate for BV due to its antimicrobial and immunomodulatory properties. Experimental models have shown that S. cerevisiae-based formulations can suppress the virulence of G. vaginalis by downregulating biofilm-associated and toxin-producing genes, thereby weakening the pathogen’s ability to persist and evade treatment.^[3] This modulation of host immunity enhances mucosal healing and reduces the risk of symptom recurrence.

Meta-analyses of clinical trials further support the efficacy of probiotic therapies in BV. When used alone or in combination with antibiotics, probiotics significantly increase cure rates and reduce recurrence compared to antibiotic therapy alone. Patients receiving probiotic supplementation report improved tolerability, enhanced vaginal comfort, and fewer adverse effects and better long-term outcomes.^[4] These consistent therapeutic effects, combined with well-characterized mechanisms of antimicrobial action and immune regulation, affirm the value of probiotics as host-compatible MBTIs for bacterial vaginosis.

Microbial Effects Summary Table

Validation of the Microbiome Signature of BV

The microbiome signature of BV is defined by the depletion of dominant Lactobacillus species—particularly Lactobacillus crispatus—and the expansion of anaerobic bacteria such as Gardnerella vaginalis, Prevotella, Mobiluncus, and Atopobium vaginae. This shift disrupts the protective functions of the vaginal microbiota, facilitates pathogen persistence, and correlates with increased inflammatory responses.^[7] Probiotic therapy directly counters this microbial profile by promoting the recolonization of beneficial lactobacilli while suppressing the growth of BV-associated anaerobes. Studies show that after probiotic administration, levels of G. vaginalis, Prevotella, and Mobiluncus decrease significantly, while L. crispatus reestablishes itself as the dominant taxon, restoring a healthy microbial equilibrium.^[8]

These microbial shifts closely mirror the inverse of the BV diagnostic signature, confirming that probiotic-induced remodeling is not random but precisely targets the taxa known to drive disease. This alignment provides compelling validation for the BV microbiome signature and highlights its clinical utility as a biomarker of dysbiosis and therapeutic response. In this context, the probiotic-induced correction of microbial patterns becomes both a therapeutic outcome and a diagnostic affirmation.

Dual Validation

The dual impact of probiotic therapy, restoring microbial balance while improving clinical outcomes, confirms its legitimacy as a microbiome-targeted intervention. The documented increase in Lactobacillus crispatus, alongside the suppression of anaerobic pathogens and reduction in inflammation, demonstrates how probiotics effectively reestablish a healthy vaginal microbiome and promote symptom resolution. At the same time, the close alignment between the microbial effects of probiotics and the core features of the BV microbiome signature provides strong, bidirectional validation: the therapeutic efficacy of the intervention confirms the relevance of the microbial signature, and the signature offers a reliable target for precision microbiome modulation. Together, these findings underscore the potential of probiotics to refine both therapeutic strategies and clinical diagnostics within microbiome-based medicine.

Research Feed

References

1. Bacterial Vaginosis: What Do We Currently Know?. Abou Chacra L, Fenollar F, Diop K.. (Front Cell Infect Microbiol. 2022 Jan 18;11:672429)
2. Lactobacillus crispatus inhibits growth of Gardnerella vaginalis and Neisseria gonorrhoeae on a porcine vaginal mucosa model. Breshears LM, Edwards VL, Ravel J, Peterson ML.. (BMC Microbiol. 2015 Dec 9;15:276)
3. Saccharomyces cerevisiae-based probiotic as novel anti-microbial agent for therapy of bacterial vaginosis. Sabbatini S, Monari C, Ballet N, Mosci P, Decherf AC, Pélerin F, Perito S, Scarpelli P, Vecchiarelli A.. (Virulence. 2018 Dec 31;9(1):954-966)
4. Probiotics are a good choice for the treatment of bacterial vaginosis: a meta-analysis of randomized controlled trial. Chen, R., Li, R., Qing, W. et al.. (Reprod Health 19, 137 (2022))
5. Lactobacillus crispatus inhibits growth of Gardnerella vaginalis and Neisseria gonorrhoeae on a porcine vaginal mucosa model. Breshears LM, Edwards VL, Ravel J, Peterson ML.. (BMC Microbiol. 2015 Dec 9;15:276)
6. Saccharomyces cerevisiae-based probiotic as novel anti-microbial agent for therapy of bacterial vaginosis. Sabbatini S, Monari C, Ballet N, Mosci P, Decherf AC, Pélerin F, Perito S, Scarpelli P, Vecchiarelli A.. (Virulence. 2018 Dec 31;9(1):954-966)
7. Bacterial Vaginosis: What Do We Currently Know?. Abou Chacra L, Fenollar F, Diop K.. (Front Cell Infect Microbiol. 2022 Jan 18;11:672429)
8. Probiotics are a good choice for the treatment of bacterial vaginosis: a meta-analysis of randomized controlled trial. Chen, R., Li, R., Qing, W. et al.. (Reprod Health 19, 137 (2022))