Antibacterial effect of cell-free supernatant fraction from Lactobacillus paracasei CH88 against Gardnerella vaginalis

Abstract

Bacterial vaginosis (BV) is the most common vaginal infection in reproductive women, which is characterized by depleted level of lactic acid bacteria and overgrowth of anaerobes such as Gardnerella vaginalis spp. Lactic acid bacteria have been known to be beneficial for amelioration of BV, since they produce antimicrobial substances against G. vaginalis spp. The objectives of this study were to characterize different fractions of cell-free supernatant of Lactobacillus paracasei CH88 (LCFS) and investigate antibacterial activity of the LCFS fractions against G. vaginalis in-vitro and in-vivo. Antibacterial activity of the LCFS was stable during thermal treatment up to 120 °C for 30 min and maintained at pH ranging from 3.0 to 13.0 except pH 5.0. Fraction below 3 kDa of the LCFS partially lost its antibacterial activity after treatment with proteolytic enzymes. Precipitated protein fraction below 3 kDa of the LCFS (< 3 kDa LCFSP) inhibited the growth and biofilm formation of G. vaginalis. Treatment of L. paracasei CH88 or the < 3 kDa LCFSP attenuated G. vaginalis-induced BV in mice by inhibiting the growth of G. vaginalis, reducing exfoliation of vaginal epithelial cells, and regulating immune response. These results suggest that L. paracasei CH88 may have potential in ameliorating G. vaginalis-induced BV.

Lactobacillus helveticus HY7801 ameliorates bacterial vaginosis by inhibiting biofilm formation and epithelial cell adhesion of Gardnerella vaginalis

“…Interestingly, the CFS of HY7801 did not significantly inhibit GV biofilm formation (Fig. 3B), unlike previous studies that showed that the CFS of specific probiotics inhibited GV biofilm formation (Moon et al, 2022;Qian et al, 2021). Therefore, in order to exclude the effects of lactic acid and H 2 O 2 , GV and HY7801 were co-cultured in fresh media, and the expression of GV virulence factor genes related to immune avoidance, epithelial cell attachment, biofilm formation, and energy metabolism was confirmed.…”

“…Vaginal epithelial cell exfoliation, a major clinical feature of BV, has been reported to be associated with increased transitional epithelial proliferation of the vagina (Bautista et al, 2016;Moon et al, 2022). Therefore, the effect of HY7801 on histological changes of vaginal tissues in GVinfected BV mice was investigated through histopathological analysis.…”

“…The inhibitory activity of WBC and CFS against GV biofilm formation was investigated according to the method described in a previous study (Moon et al, 2022). GV (1.0 × 10 7 CFU/mL) was inoculated into a 24-well highbinding tissue culture plate with 0.9 mL of BHIS broth, and 100 μL of WBC or CFS of each LAB strain was added.…”

Reference Lactobacillus strains as Potential Antimicrobial Agents Against Priority Pathogens with Different Levels of Drug Resistance

“…In terms of approaches for controlling antibiotic-resistant pathogens, a spectrum of strategies is being investigated, from novel antibiotic development to phage therapy. However, there has been increasing attention on the utilization of probiotics, notably Lactobacillus strains, in this context 15,40,41 . This focus is substantiated by the generally safe pro le of Lactobacillus, its minimal side-effects, and its capacity to modulate both microbial antagonism and host immune response 11 .…”

Optimization of growth of Levilactobacillus brevis SP 48 and in vitro evaluation of the effect of viable cells and high molecular weight potential postbiotics on Helicobacter pylori

“…polysaccharides, proteins, fatty acids, peptides, and organic acids) are biologically active molecules that often optimize physiological and immune functions of the host and provide numerous benefits. Cell-free supernatants of lactobacilli have frequently been shown to possess antimicrobial properties due to the presence of organic acids and bacteriocins ( Yang et al, 2021 ; Moon et al, 2022 ). The supernatants obtained from the growth of L. brevis SP 48 were here investigated to study the effects of a polysaccharide- and protein-enriched secreted fraction, deprived of organic acids and bacteriocins removed by ultrafiltration.…”