Local Probiotic Lactobacillus crispatus and Lactobacillus delbrueckii Exhibit Strong Antifungal Effects Against Vulvovaginal Candidiasis in a Rat Model.

Ting Li,Xu Zhang,Zhaohui Liu,Xi Chen,Suxia Wang

doi:10.3389/fmicb.2019.01033

Abstract

A comprehensive knowledge of the vaginal ecosystem is critical for the development of successful approaches to the treatment of infections. The role of Lactobacilli in preventing vulvovaginal candidiasis (VVC) is controversial. In this study, we investigated the therapeutic effects and mechanism of Lactobacillus crispatus or delbrueckii on vaginitis caused by Candida albicans in a Sprague–Dawley rat model. A microbiological evaluation was performed by Gram staining and fungal colonies were enumerated. The antifungal efficacy of the two Lactobacillus strains was assessed by hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), immunohistochemical detection of interferon-γ (IFN-γ), interleukin (IL)-4, IL-17, and epithelial-derived IgG (RP125). Our in vitro results showed that the inhibitory activity against Candida colony-forming unit (CFU) counts was demonstrated by the two Lactobacillus strains (P < 0.001). Our results indicated that Lactobacillus administration played an indispensable role in maintaining the immune homeostasis, and decreasing the Th1/Th2 ratio (IFN-γ/IL-4) by regulating the epithelial secretion of cytokines that inhibit epithelial proinflammatory cytokine release, while increasing epithelial-derived IgG expression (P < 0.05), suggesting antibody-mediated protection. Our results implicate L. crispatus and L. delbrueckii as a potential adjunct biotherapeutic agent in women with VVC, especially for those with drug resistance, adverse effects or contraindications when using antifungal agents. Further large, long-term, well-planned clinical studies should be performed in clinical practice to determine their clinical potential of L. crispatus and L. delbrueckii as an adjunct treatment for VVC.

Highlights

It is well accepted that the microbiota present in the human body can impact immunity, physiology, and health (Song et al, 2018)
The Lactobacilli present in the vagina are important in preventing vaginal infections, such as bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC), and invasion by pathogenic microorganisms, including human papillomavirus, and human immunodeficiency virus (Reid and Bocking, 2003)
The use of Lactobacilli-derived probiotic bacteria has emerged as a novel strategy for the management of vaginal infections

Summary

Introduction

It is well accepted that the microbiota present in the human body can impact immunity, physiology, and health (Song et al, 2018). It has been postulated that the unique vaginal microbiome has evolved to perform the dual roles of disease resistance and obstetric protection (Amabebe and Anumba, 2018). Infections can arise from imbalances in the highly diverse vaginal microbiota (e.g., VVC). VVC, caused primarily by Candida, is the second-most common vaginal infecti and is associated with vulval discomfort or and pain (Dovnik et al, 2015). The recommended standard therapy for vaginal C. albicans infections is antifungal therapy, consisting of oral or intravaginal azole, or triazole drugs (Sobel and Sobel, 2018). Prolonged use of antibiotic administration increases recurrence rates, probably due to an inability to re-establish the normal Lactobacillus-dominated vaginal flora

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