Sialidase Activity in the Cervicovaginal Fluid Is Associated With Changes in Bacterial Components of Lactobacillus-Deprived Microbiota

Abstract

IntroductionSialidase activity in the cervicovaginal fluid (CVF) is associated with microscopic findings of bacterial vaginosis (BV). Sequencing of bacterial 16S rRNA gene in vaginal samples has revealed that the majority of microscopic BV cases fit into vaginal community-state type IV (CST IV), which was recently named “molecular-BV.” Bacterial vaginosis-associated bacterial species, such as Gardnerella spp., may act as sources of CVF sialidases. These hydrolases lead to impairment of local immunity and enable bacterial adhesion to epithelial and biofilm formation. However, the impact of CVL sialidase on microbiota components and diversity remains unknown.ObjectiveTo assess if CVF sialidase activity is associated with changes in bacterial components of CST IV.MethodsOne hundred forty women were cross-sectionally enrolled. The presence of molecular-BV (CST IV) was assessed by V3–V4 16S rRNA sequencing (Illumina). Fluorometric assays were performed using 2-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid (MUAN) for measuring sialidase activity in CVF samples. Linear discriminant analysis effect size (LEfSe) was performed to identify the differently enriched bacterial taxa in molecular-BV according to the status of CVF sialidase activity.ResultsForty-four participants (31.4%) had molecular-BV, of which 30 (68.2%) had sialidase activity at detectable levels. A total of 24 bacterial taxa were enriched in the presence of sialidase activity, while just two taxa were enriched in sialidase-negative samples.ConclusionSialidase activity in molecular-BV is associated with changes in bacterial components of the local microbiome. This association should be further investigated, since it may result in diminished local defenses against pathogens.

The Vaginal Microbiota in Early Pregnancy Identifies a Subset of Women at Risk for Early Preterm Prelabor Rupture of Membranes and Preterm Birth

“…are associated with both bacterial vaginosis 108,109 and intra-amniotic infection [110][111][112] . They are key producers of the enzyme sialidase, which can degrade the mucosa of the vaginal epithelium, resulting in tissue damage 108, 109,113,114 . The genus Sneathia has two species, S. sanguinegens and S. vaginalis (formerly S. amnii 115 ).…”

Gardnerella vaginalis clades in pregnancy: New insights into the interactions with the vaginal microbiome

“…Recently, Ferreira et al . observed that many BV-related taxa (especially belonging to Prevotella genera) were enriched in sialidase-positive vaginal samples and that only two taxa, including Lactobacillus helveticus , were associated with sialidase-negative samples [ 7 ].…”

“…Among these species, Gardnerella vaginalis (GV) is thought to play a key role in the pathogenesis of BV [ 5 ]. Indeed, GV can produce various virulence factors—including sialidase, a hydrolase able to degrade local immunoglobulin A (IgA) and vaginal mucins, likely contributing to the diminished viscosity of local secretion, resulting in an increased vulnerability to pathogens [ 6 , 7 ]. Moreover, GV has a great ability to form a biofilm acting as a scaffold to which other anaerobic species, such as Atopobium vaginae and Prevotella spp., can subsequently attach [ 8 , 9 ].…”

Vaginal Lactobacillus iners abundance is associated with outcome in antibiotic treatment of bacterial vaginosis and capable of inhibiting Gardnerella

“…In recent years, researchers have isolated and identified 9 genomospecies of Gardnerella through cpn60 gene typing, whole genome sequencing and other methods ( Schellenberg et al., 2016 ; Schellenberg et al., 2017 ; Hill and Albert, 2019 ; Vaneechoutte et al., 2019 ; Qin and Xiao, 2022 ). Many investigations have focused on identifying the differences in the ability to adhere to vaginal epithelial cells, virulence and drug resistance among genomospecies and the relevance of the distribution of Gardnerella genomospecies with the occurrence, symptoms or clinical outcome of BV, but the results lack consistency ( Santiago et al., 2011 ; Onderdonk et al., 2016 ; Hardy et al., 2017 ; Hilbert et al., 2017 ; Deng et al., 2018 ; Janulaitiene et al., 2018 ; Ferreira et al., 2021 ; Khan et al., 2021 ).…”