Role of Probiotics in recurrent bacterial vaginosis: A review

Though antibiotics like metronidazole and clindamycin have been regarded as the conventional drug therapy to manage BV, the recurrence rates remain high (3) owing to the rise of new drug-resistant microbial variants and antibiotic side effects. This has opened the field for use of probiotics, which are now considered to be an efficient alternative strategy to treat BV, by restoring the healthy vaginal microbial ecosystem.

What causes the frequent recurrence of bacterial vaginosis?

Elimination of the commensal organisms in the vagina by antimicrobial therapy, thereby increasing susceptibility to recolonization by pathogens is one of the major causes of high recurrence. Further, antimicrobials fail to eradicate the pathogens, due to biofilm resistance, coupled with the virulent organisms coming back from their source (the person's gut, or partner) and attacking the host whose defenses are suboptimal adds up to the problem. (1)

Role of Probiotics: How do they act?

Probiotics are 'live microorganisms that, when administered in adequate amounts, confer a health benefit on the host' (3). Lactobacillus, Bifidobacterium, Streptococcus, Enterococcus, and Bacillus- are some of the most common beneficial probiotic microorganisms in use today. (4)

BV is characterized by a significant decline in lactic acid-producing lactobacilli, alteration of the optimal vaginal pH, disruption of the vaginal barrier by hydrolytic enzymes, increased release of proinflammatory cytokines and chemokines with increased susceptibility to difficult-to-treat pathogens, and recurrent infection. (4)

In such situations, probiotics act by replenishing the commensal microbes and lowering the risk of reinfection. Ample evidence now suggests that probiotics provide host protection against microbial invasion by blocking the colonization of vaginal pathogens as a result of displacement and exclusion competition and promoting immunomodulation mechanisms by activating the innate immunity system, producing hydrogen peroxide (H2O2), and stimulating anti-inflammatory action. (4)

In post-menopausal women, receding estrogen levels are associated with a decrease in vaginal lactobacilli colonization and adherence, making them more susceptible to urogenital infections, and colonization of the vagina by commensal lactobacilli will serve as a protection against pathogens. (1) Such encouraging results have made lactobacilli species and their various combinations the most studied probiotic to date.

Revealing Study testimonials: Notable studies supporting the use of probiotics in BV

An accumulating body of evidence now supports the eminent role of probiotics in the restoration of vaginal normal flora and in treating bacterial vaginosis.

1. Analyzing the effect of oral probiotics containing Lactobacillus rhamnosus and L. reuteri on women infected with bacterial vaginosis, Anukam et al. (5) noted a remarkable 90% recovery rate in women with BV after probiotic administration to women treated with antibiotics.

2. Another study by Mastromarino et al. (6), highlighted a drastic improvement of the vaginal microbiome among BV infected women, as 83% of the women in the test group were free of BV after therapy with Lactobacillus.

3. In a one of its kind study, Ling et al. (7) showed that probiotic administration has a better effect than the classical antibiotics in treating BV. They found that both 7-day intravaginal metronidazole and 10-day intravaginal probiotics have good efficacy against BV, but probiotics maintained normal vaginal microbiota longer due to effective and steady vaginal microbiota restoration.

4. The efficacy of combining probiotics or placebo with oral metronidazole was assessed in 125 women aged 18 to 44 with BV. Researchers noted a cure rate of 40% in placebo and 88% in probiotic subjects, affirming that probiotics can augment the effects of antibiotics in managing BV. (8)

5. A study by Bastani et al confirmed the potential efficacy of lactobacilli in restoring and maintaining the normal urogenital flora and showed that probiotic bacteria when supplemented for 2 months can most appropriately normalize vaginal flora, help cure the existing infection and prevent recurrence of BV. They also elaborated that longer periods of probiotic administration may be useful for long-term control of BV relapses after conventional antibiotic therapy. (4)

6. Yet another recent study aimed at investigating the efficiency of long-term Lactobacillus administration in restoring vaginal microbiota among 250 nonpregnant women with BV over 9 months, has confirmed the pivotal role of Lactobacillus as prophylactic therapy in suppressing BV recurrence, even after antibiotic treatment. (4)

7. Evaluating the antimicrobial effect of two Lactobacillus strains (Lactobacillus rhamnosus and Lactobacillus acidophilus) alone or in combination, the results from a study have revealed that the combination of the strains exerts a synergic activity against Escherichia coli, thus augmenting recovery from BV. (9)

8. A study by Rukshana Shamshu et al reported that in the treatment of bacterial vaginosis, the addition of probiotics (Lactobacillus rhamnosus and Lactobacillus reuteri) to the conventional antibiotics can improve the cure rate of bacterial vaginosis and reduce the rate of recurrences. (10)

Backed by such positive results, it is not surprising that probiotics as adjunctive and alternative medicine is already being widely used particularly in those with chronic vaginitis.

Highlights-

1. Maintaining a harmonious balance of vaginal microbiota is crucial to preventing recurrent BV.

2. Probiotics are being considered the latest armamentarium to ward off BV by replenishing the vaginal microbiome, restoring physiological homeostasis and host function, including reducing hostile bacteria, regulating the immune system, preventing infection, and promoting overall reproductive health.

3. As evidence continues to support the benefits of probiotics not only treating, but also preventing bacterial vaginosis, practitioners should be optimistic about recommending them to their full potential as and when needed.

Conclusion-Accounting for a global prevalence of between 23% to 29% (4) across different regions, BV is emerging to be a grave and costly health burden. Though drug therapy is effective in the relief of symptoms typically associated with acute infections, they are generally unable to offer long-term protection against possible recurrences. Given the unique mechanism of action of probiotics, along with its good safety and tolerability profile, the future direction of managing BV lies in considering this therapy as an effective and viable strategy against recurrent cases of BV.

The above article has been published by Medical Dialogues under the MD Brand Connect Initiative. For more details on Probiotics, click here.

References

1. Cribby, Sarah; Taylor, Michelle; Reid, Gregor (2008). Vaginal Microbiota and the Use of Probiotics. Interdisciplinary Perspectives on Infectious Diseases, 2008(), 1–9. doi:10.1155/2008/256490

2. Dr. Anshu Mishra. Analysis of vaginal infections in pregnant women: A clinical study. Int J Clin Obstet Gynaecol 2018;2(1):10-12.

3. Superti, F., & De Seta, F. (2020). Warding Off Recurrent Yeast and Bacterial Vaginal Infections: Lactoferrin and Lactobacilli. Microorganisms, 8(1), 130. https://doi.org/10.3390/microorganisms8010130

4. Yue Han, Qing-ling Ren, Does probiotics work for bacterial vaginosis and vulvovaginal candidiasis, Current Opinion in Pharmacology, Volume 61,2021, Pages 83-90, ISSN 1471-4892,https://doi.org/10.1016/j.coph.2021.09.004

5. Anukam KC, Osazuwa E, Osemene GI, Ehigiagbe F, Bruce AW, Reid G: Clinical study comparing probiotic Lactobacillus GR-1 and RC-14 with metronidazole vaginal gel to treat symptomatic bacterial vaginosis. Microbes Infect 2006, 8: 2772–2776.

6. Mastromarino P, Macchia S, Meggiorini L, et al.: Effectiveness of Lactobacillus-containing vaginal tablets in the treatment of symptomatic bacterial vaginosis. Clin Microbiol Infect 2009, 15:67–74.

7. Ling Z, Liu X, Chen W, et al.: The restoration of the vaginal microbiota after treatment for bacterial vaginosis with metronidazole or probiotics. Microbiol 2013, 65:773–780

8. K. Anukam, E. Osazuwa, I. Ahonkhai, et al., "Augmentation of antimicrobial metronidazole therapy of bacterial vaginosis with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14: randomized, double-blind, placebo-controlled trial," Microbes and Infection, vol. 8, no. 6, pp. 1450–1454, 2006.

9. Bertuccini, L.; Russo, R.; Iosi, F.; Superti, F. Effects of Lactobacillus rhamnosus and Lactobacillus acidophilus on bacterial vaginal pathogens. Int. J. Immunopathol. Pharmacol. 2017, 30, 163–167.

10. International Journal of Reproduction, Contraception, Obstetrics and Gynecology Shamshu R et al. Int J ReprodContraceptObstet Gynecol. 2017 Feb;6(2):671-681 www.ijrcog.org