Molecular assessment of bacterial vaginosis by Lactobacillus abundance and species diversity.

Joke A M Dols,Jannie J Van Der Helm,Henry J C De Vries,Hans V Westerhoff,Remco Kort,Frank H J Schuren,Douwe Molenaar,Adrianus G C L Speksnijder,Alie De Kat Angelino-Bart,Mathilde E Boon,Martien P M Caspers,Jan Hendrik Richardus,Gregor Reid

doi:10.1186/s12879-016-1513-3

Abstract

BackgroundTo date, women are most often diagnosed with bacterial vaginosis (BV) using microscopy based Nugent scoring or Amsel criteria. However, the accuracy is less than optimal. The aim of the present study was to confirm the identity of known BV-associated composition profiles and evaluate indicators for BV using three molecular methods.MethodsEvaluation of indicators for BV was carried out by 16S rRNA amplicon sequencing of the V5-V7 region, a tailor-made 16S rRNA oligonucleotide-based microarray, and a PCR-based profiling technique termed IS-profiling, which is based on fragment variability of the 16S-23S rRNA intergenic spacer region. An inventory of vaginal bacterial species was obtained from 40 females attending a Dutch sexually transmitted infection outpatient clinic, of which 20 diagnosed with BV (Nugent score 7–10), and 20 BV negative (Nugent score 0–3).ResultsAnalysis of the bacterial communities by 16S rRNA amplicon sequencing revealed two clusters in the BV negative women, dominated by either Lactobacillus iners or Lactobacillus crispatus and three distinct clusters in the BV positive women. In the former, there was a virtually complete, negative correlation between L. crispatus and L. iners. BV positive subjects showed cluster profiles that were relatively high in bacterial species diversity and dominated by anaerobic species, including Gardnerella vaginalis, and those belonging to the Families of Lachnospiraceae and Leptotrichiaceae. Accordingly, the Gini-Simpson index of species diversity, and the relative abundance Lactobacillus species appeared consistent indicators for BV. Under the conditions used, only the 16S rRNA amplicon sequencing method was suitable to assess species diversity, while all three molecular composition profiling methods were able to indicate Lactobacillus abundance in the vaginal microbiota.ConclusionAn affordable and simple molecular test showing a depletion of the genus Lactobacillus in combination with an increased species diversity of vaginal microbiota could serve as an alternative and practical diagnostic method for the assessment of BV.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1513-3) contains supplementary material, which is available to authorized users.

Highlights

To date, women are most often diagnosed with bacterial vaginosis (BV) using microscopy based Nugent scoring or Amsel criteria
Bacterial vaginosis and sexually transmitted infection (STI)-status A total of 40 cervical swab samples were collected from women older than 18 years of age
According to the Amsel criteria, 21 women were positive for BV, with only one discrepancy between the Amsel and Nugent method

Summary

Introduction

Women are most often diagnosed with bacterial vaginosis (BV) using microscopy based Nugent scoring or Amsel criteria. Bacterial vaginosis (BV) is an aberrant state of the vaginal microbiota, which is characterized by a depletion of lactobacilli, an increased diversity of the bacterial population and an elevated pH. It is one the most common vaginal syndromes in fertile, premenopausal and pregnant women [1]. Diagnoses based on the Amsel criteria [6], and microscopic methods, such as the Nugent score [7], have their limitations. As a result of the rapid development of sequencing platforms, they have become more affordable and accurate

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