Antibacterial Activity of Lactobacillus Strains Isolated from Mongolian Yogurt against Gardnerella vaginalis

Abstract

Worldwide interest in the use of functional foods containing probiotic bacteria such as Lactobacillus and Bifidobacterium for health promotion and disease prevention has increased significantly. Probiotics have demonstrated beneficial properties including strengthening the body’s natural defense system, inhibiting the growth of pathogenic bacteria, and regulating mental activity, but their effects on the human vagina have not been fully elucidated. The primary purpose of our study was to isolate Lactobacillus strains from old yogurt, a traditional dairy product, and investigate their probiotic potential with respect to the human vaginal system. Four Lactobacillus plantarum (L. plantarum) strains, named ZX1, ZX2, ZX27, and ZX69, were isolated from the yogurt samples. Simultaneously, we used a commercial Lactobacillus strain (Lactobacillus delbrueckii DM8909) as a control strain. We tested the antimicrobial activity of Lactobacillus isolates against Escherichia coli and Gardnerella vaginalis by agar spot and well diffusion tests. Then, we tested the antibiotic susceptibility of the 5 strains by using the minimal inhibitory concentration method. We attempted to detect possible bacteriocin genes by PCR sequencing technique. Using a chemically defined medium simulating genital tract secretions, we found that the selected Lactobacillus strains could alter the expression of known virulence genes in Gardnerella vaginalis. Bacteriocins derived from these isolated strains had potent antibacterial activity against G. vaginalis and E. coli, with the most effective activity observed in the case of ZX27. In addition, all strains including the L. delbrueckii DM8909 were positive for the presence of the plantaricin cluster of genes described in L. plantarum C11. The tested stains possessed the pln gene indicating that one of the antibacterial agents was plantaricin. We assume that the production of antimicrobial substances such as bacteriocins induce G. vaginalis to upregulate antimicrobial resistance genes. The new isolated strains have bacteriocin-related genes and can change the antimicrobial resistance gene transcription of G. vaginalis.

Probiotic Lactobacillus sp. Strains Inhibit Growth, Adhesion, Biofilm Formation, and Gene Expression of Bacterial Vaginosis-Inducing Gardnerella vaginalis

“…In our previous study, Lactobacillus sp. directly inhibited bcrA and mds expression [ 24 ]. This phenomenon might explain the better potency of probiotics combined with antibiotics for BV therapy compared to antibiotics alone [ 5 ].…”

“…CFS from the three Lactobacillus sp. strains were prepared as described in our previous study [ 24 ]. Briefly, Lactobacillus sp.…”

“…Lpb. plantarum ZX27 is a typical probiotic microorganism found in old yogurt, and we previously demonstrated its antimicrobial effects against G. vaginalis and Escherichia coli [ 24 ]. However, to date, no study has investigated the anti-biofilm effect of Lpb.…”

Diverse Gene Cassette Arrays Prevail in Commensal Escherichia coli From Intensive Farming Swine in Four Provinces of China

“…The increasing prevalence of MDR E. coli and other antimicrobial-resistant microorganisms causes unpredictable consequences to the environment and humans. In China, alternative strategies have been effectively explored to combat veterinary antimicrobial resistance, such as vaccination, chicken egg yolk antibodies ( Zhang et al, 2011 ), lactic acid bacteria ( Yang et al, 2015 ), antimicrobial peptides ( Kang et al, 2017 ), bacteriocins ( Qian et al, 2020 ), antibiotic adjuvants ( Liu et al, 2019 ), phytocompounds ( Chang et al, 2019 ), and metal-based nanoparticles ( Ali et al, 2020 ). In addition, the implementation of management strategies has been done to reduce antimicrobial usage in animal husbandry, including good hygiene practice and biosecurity measures ( Hu and Cowling, 2020 ).…”

Lactobacillus rhamnosus AD3 as a Promising Alternative for Probiotic Products

“…In this context, the use of probiotics consisting of Lactobacillus spp. is increasing in the gynaecological field to restore the physiologic vaginal microbiota and treat bacterial vaginosis and vulvovaginal candidiasis even if there is conflicting evidence between them [ 14 , 15 , 16 ]. Although the local administration should be the best and fastest solution to the problem of vaginal dysbiosis, main scientific concept associated with the use of probiotics is the oral administration of live microorganisms in order to restore the environment by competition [ 17 ].…”