A New PNA-FISH Probe Targeting Fannyhessea vaginae.

Lúcia G V Sousa,Carina Almeida,Nuno Cerca,Christina A Muzny,Joana Castro,Angela França

doi:10.3389/fcimb.2021.779376

Abstract

Bacterial vaginosis (BV) is the most common vaginal infection in women of reproductive age and has been associated with serious health complications, mainly in pregnant women. It is characterized by a decrease in the number of Lactobacillus species in the healthy vaginal microbiota and an overgrowth of strict and facultative anaerobic bacteria that develop a polymicrobial biofilm. Despite over 60 years of research investigating BV, its etiology is not fully understood. Gardnerella spp. is a crucial microorganism that contributes to the formation of the biofilm and the development of BV, but the role of other BV-associated bacteria is not clear. Nevertheless, Fannyhessea vaginae (previously known as Atopobium vaginae) is a highly specific species for BV, and co-colonization with Gardnerella is thought to be a very specific diagnostic marker. The diagnosis of BV still presents some limitations, since currently used methods often fail to accurately detect BV. This work aims to develop a novel peptide nucleic acid (PNA) probe targeting F. vaginae. This probe was further validated in a multiplex assay, which included a Gardnerella-specific PNA probe, as a possible method for diagnosis of BV, and was compared with quantification by qPCR. The new PNA probe showed excellent sensitivity and specificity and could discriminate F. vaginae-Gardnerella biofilms, confirming the potential to be used for the detection of BV-associated pathogens.

Highlights

Bacterial vaginosis (BV) is the most common vaginal infection in women of reproductive age (Jung et al, 2017) affecting around 23% to 29% of women worldwide and it is associated with high healthcare costs (Peebles et al, 2019)
BV is characterized by a decrease in commensal, protective lactobacilli and a dramatic increase in strict and facultative anaerobic bacteria which form a polymicrobial biofilm on the surface of the vaginal epithelial cells (Turovskiy et al, 2011; Rosca et al, 2020b)
When evaluating the Nugent method using the Amsel criteria as reference, the values of sensitivity and specificity range from 78% to 94% and 67% to 94%, respectively, (Schwebke et al, 1996) and more reliable and accurate alternatives for the detection of bacteria associated with BV are needed to improve diagnosis (Africa, 2013; Redelinghuys et al, 2020)

Summary

Introduction

Bacterial vaginosis (BV) is the most common vaginal infection in women of reproductive age (Jung et al, 2017) affecting around 23% to 29% of women worldwide and it is associated with high healthcare costs (Peebles et al, 2019). The most common method for BV diagnosis is Amsel’s criteria, which is based on criteria related to the clinical signs of BV These criteria include (i) homogeneous vaginal discharge, (ii) vaginal pH greater than 4.5, (iii) the release of a fishy smell on the addition of 10% potassium hydroxide to a drop of vaginal discharge, and (iv) the presence of clue cells (Amsel et al, 1983). When evaluating the Nugent method using the Amsel criteria as reference, the values of sensitivity and specificity range from 78% to 94% and 67% to 94%, respectively, (Schwebke et al, 1996) and more reliable and accurate alternatives for the detection of bacteria associated with BV are needed to improve diagnosis (Africa, 2013; Redelinghuys et al, 2020)

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