Lactobacillus: screening from human reproductive tract and therapeutic effect on a mouse model of vulvovaginal candidiasis

Abstract:

[Objective] To isolate probiotic Lactobacillus strains from the human reproductive tract and explore the therapeutic effect of the strains on vulvovaginal candidiasis. [Methods] We used the de Man, Rogosa and Sharpe agar containing 1% calcium carbonate to isolate the Lactobacillus strains from the vaginal secretions of asymptomatic women in the childbearing age, screened the strains by using the co-culture method with Candida albicans, and then examined their physiological properties. The inhibitory effect of Lactobacillus was further evaluated in a mouse model of vulvovaginal candidiasis. [Results] Nineteen strains of Lactobacillus sp. were isolated from 53 samples. Among of them, 4 strains, i.e., L. crispatus ZH08, L. fermentum ZH09, L. fermentum ZH11, and L. crispatus ZH17, showed strong inhibitory effect against C. albicans, and grew well in a low-pH environment. L. fermentum ZH09 and ZH11 inhibited the growth of C. albicans, with the inhibition effect over 95% within 24 h. L. crispatus ZH08 and ZH17 had strong aggregation property and demonstrated strong adhesion to epithelial cells. Furthermore, the combination of L. fermentum ZH11 and L. crispatus ZH17 significantly inhibited the growth and the switch from budding to hyphal growth of C. albicans, promoted mucosal repair, and relieved inflammation in a mouse model of vulvovaginal candidiasis. [Conclusion] The screened Lactobacillus strains have probiotic properties and the potential in clinical application.