Evaluation of the Inhibitory Effects of Lactobacillus gasseri and Lactobacillus crispatus on the Adhesion of Seven Common Lower Genital Tract Infection-Causing Pathogens to Vaginal Epithelial Cells

Abstract

Background/Purpose: Lactobacillus colonization is important to maintain urogenital flora stability and prevent pathogenic infection. Different Lactobacillus species have distinct properties and effects on the urogenital flora. To select probiotics that colonize the vagina and provide protection against pathogenic infection, we evaluated the adhesion of five Lactobacillus strains and their inhibitory effects on the adhesion of pathogens to vaginal epithelial cells (VECs). Methods and Materials: (1) Lactobacillus adhesion experiments: VK2/E6E7 and primary VECs were used to evaluate the adhesion of two Lactobacillus gasseri and three Lactobacillus crispatus strains. The adhesion of these five Lactobacillus strains was compared. (2) Adhesion inhibition experiments: The inhibitory effects of the five Lactobacillus strains on the adhesion of pathogens (Gardnerella, Mobiluncus, Candida albicans, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis) were evaluated by adhesion exclusion, displacement, and competition experiments. Results: (1) Lactobacillus adhesion was stronger in the primary VECs than in the VK2/E6E7 VECs (P < 0.05). The adhesion of the three L. crispatus strains was stronger than that of the two L. gasseri strains (P < 0.05). L. crispatus 4# showed the strongest adhesion. (2) The exclusion, displacement, and competition experiments showed that all five Lactobacillus strains significantly inhibited the adhesion of the seven pathogenic strains to the VECs (P < 0.05). The displacement effect was stronger than the exclusion and competition effects of each Lactobacillus strain. (3) The results of the exclusion, displacement, and competition experiments indicated that L. gasseri 1# showed the strongest adhesion inhibition of C. albicans and S. agalactiae. L. crispatus 3# showed the strongest adhesion inhibition of S. aureus, whereas L. crispatus 4# showed the strongest adhesion inhibition of Gardnerella, Mobiluncus, E. coli, and E. faecalis. He et al. Effects of Lactobacillus on Pathogens Conclusion: The source of the VECs might not affect the selection of the most adhesive Lactobacillus strain. L. crispatus showed stronger VEC adhesion than L. gasseri. The degree of antagonism of the Lactobacillus strains toward the different pathogens varied. This result provides incentives for personalized clinical treatment.

Potential of mucoadhesive chitosan glutamate microparticles as microbicide carriers – antiherpes activity and penetration behavior across the human vaginal epithelium

“…Thus, the goal was to assess the antiviral effect of gCS microparticles toward HSV-2 infection using viral attachment and penetration assay. The tests were performed in two keratinocyte cell lines commonly used to study microbicides in vitro (Michaelis et al, 2019 ; He et al, 2020 ). To test whether viral binding to the cell surface can be affected, HaCaT and VK2-E6/E7 cells were initially incubated at 4.0 ± 1 °C with HSV-2 in the presence of gCS microparticles, then the temperature was raised to 37.0 ± 1 °C to allow the virus to enter the cells.…”

Bacterial and Host Determinants of Group B Streptococcal Vaginal Colonization and Ascending Infection in Pregnancy

“…Mechanisms by which Lactobacilli restrain GBS colonization at the microbiome-level remain unclear, but multiple studies have partially defined the interactions between different Lactobacillus species and GBS. Lactobacilli can have antagonistic effects on the growth of GBS and host cell interactions in vitro (Bodaszewska et al, 2010;Ortiz et al, 2014;Marziali et al, 2019;He et al, 2020). While in human observational vaginal microbiome studies, the relationship between Lactobacillus-replete microbiomes and GBS colonization is less clear (Kubota et al, 2002;Altoparlak et al, 2004;Daniel Johannes Rönnqvist et al, 2006;Brzychczy-Wloch et al, 2014;Rick et al, 2017), there is evidence that reduced taxonomic diversity and Lactobacillus dominance are possible mechanisms of microbiome-based protection against GBS during pregnancy (Sroka- Oleksiak et al, 2020).…”

Finding a Balance in the Vaginal Microbiome: How Do We Treat and Prevent the Occurrence of Bacterial Vaginosis?

“…Lactobacillus spp. has been shown to exhibit inhibitory effects on pathogens by resource competition, representing another key mechanism in maintaining the colonization of the vagina [32][33][34][35]. Despite that, it is still impossible to pinpoint precisely which species or groups of Lactobacillus spp.…”