| Abstract [eng] |
Bacterial vaginosis (BV) is a highly prevalent form of vaginal microbiota imbalanc among reproductive-age women worldwide characterized by a decrease in lactobacilli and increase in various anaerobic bacteria. The bacterium Gardnerella is detected in vagina of almost all women with BV. Also it is present in some healthy women but in smaller amounts. Gardnerella shows exceptional virulent potential: it forms biofilms, produces the toxin vaginolysin, and secretes sialidases. It is believed that there are commensal and pathogenic Gardnerella strains belonging to different clades that differ in their virulence and role within the microbiota. The aim of this study: to detect Gardnerella and determine its clade in healthy and BV vaginal microbiota samples from Lithuanian women (n=109), to isolate Gardnerella strains and evaluate their virulence factors (biofilm formation, vaginolysin, and sialidase secretion) as well as their distribution among Gardnerella clades/species. Results and conclusions: Gardnerella was detected in all BV microbiota and in 87% of healthy microbiota samples. Clades 1 and 4 were identified most frequently. Multiple Gardnerella clades were associated with BV microbiota, while single-clade was characteristic of healthy microbiota. Thirty-four strains of clades 1, 2, and 4 were isolated from the vaginal samples; however, strains of the rarely detected clade 3 could not be isolated. Clade 4 strains lacked sialidase-encoding genes and sialidase activity; this may explain why this subtype is frequently found in healthy vaginal microbiota. Gardnerella clades exhibited different virulent potential: clade 4 was homogeneous, showing low expression of the tested virulence factors, while clades 1 and 2 were heterogeneous, characterized by distinct profiles of phenotypic characteristics. |
