AUTHOR=He Yuanhui , Niu Xiaoxi , Wang Ben , Na Risu , Xiao Bingbing , Yang Huixia 

TITLE=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

JOURNAL=Frontiers in Medicine

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2020.00284

DOI=10.3389/fmed.2020.00284

ISSN=2296-858X

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