Assignment of Gardnerella vaginalis clades from primary vaginal swabs

Abstract

Introduction: Gardnerella vaginalis (G. vaginalis) is the most detected bacterial species in bacterial vaginosis (BV) patients, influencing the syndrome’s pathogenesis. Limited data exist on the genetic diversity and distribution of G. vaginalis clades in South African women with BV. This study aimed to determine the prevalence and distribution of G. vaginalis clades among BV-intermediate and BV-positive South African women.
Methods: This cross-sectional study involved 150 pregnant and non-pregnant women attending the King Edward VIII Hospital in Durban, South Africa. BV was diagnosed using Nugent scoring, and G. vaginalis was detected using the Applied Biosystems™ TaqMan^® assays. Molecular genotyping of G. vaginalis positive samples was based on the diversity within the tuf gene.
Results: Of the 150 women screened for BV, 44 (29.3) were diagnosed as positive, and the same percentage of women tested were diagnosed as BV-intermediate. Mixed clades of G. vaginalis were detected in 98.1% of the samples. Clade 4 (100%) was the most prevalent clade, followed by clade 1 (98.1%), clade 3 (68.5%), and clade 2 (57.4%). Most women harbouring all four clades were asymptomatic for BV (84.6%), were not using contraceptives (76.9%), were non-pregnant (88.5%), and were living with human immunodeficiency virus (HIV) (80.8%).
Conclusion: This study was the first to report the prevalence and diversity of G. vaginalis clades in BV-intermediate and BV-positive South African women. The findings highlight the high diversity of G. vaginalis strains and the presence of multiple clades in vaginal samples, especially among asymptomatic women. It is important to understand the diversity of G. vaginalis strains and the presence of clades as they help diagnose asymptomatic women.