Date Published: July 11, 2017
Publisher: Public Library of Science
Author(s): Hanneke Borgdorff, Charlotte van der Veer, Robin van Houdt, Catharina J. Alberts, Henry J. de Vries, Sylvia M. Bruisten, Marieke B. Snijder, Maria Prins, Suzanne E. Geerlings, Maarten F. Schim van der Loeff, Janneke H. H. M. van de Wijgert, David N. Fredricks.
To evaluate whether ethnicity is independently associated with vaginal microbiota (VMB) composition in women living in Amsterdam, the Netherlands, as has been shown for American women.
Women (18–34 years, non-pregnant, N = 610) representing the six largest ethnic groups (Dutch, African Surinamese, South-Asian Surinamese, Turkish, Moroccan, and Ghanaian) were sampled from the population-based HELIUS study. Sampling was performed irrespective of health status or healthcare seeking behavior. DNA was extracted from self-sampled vaginal swabs and sequenced by Illumina MiSeq (16S rRNA gene V3-V4 region).
The overall prevalence of VMBs not dominated by lactobacilli was 38.5%: 32.2% had a VMB resembling bacterial vaginosis and another 6.2% had a VMB dominated by Bifidobacteriaceae (not including Gardnerella vaginalis), Corynebacterium, or pathobionts (streptococci, staphylococci, Proteus or Enterobacteriaceae). The most prevalent VMB in ethnically Dutch women was a Lactobacillus crispatus-dominated VMB, in African Surinamese and Ghanaian women a polybacterial G. vaginalis-containing VMB, and in the other ethnic groups a L. iners-dominated VMB. After adjustment for sociodemographic, behavioral and clinical factors, African Surinamese ethnicity (adjusted odds ratio (aOR) 5.1, 95% confidence interval (CI) 2.1–12.0) and Ghanaian ethnicity (aOR 4.8, 95% CI 1.8–12.6) were associated with having a polybacterial G. vaginalis-containing VMB, and African Surinamese ethnicity with a L. iners-dominated VMB (aOR 2.8, 95% CI 1.2–6.2). Shorter steady relationship duration, inconsistent condom use with casual partners, and not using hormonal contraception were also associated with having a polybacterial G. vaginalis-containing VMB, but human papillomavirus infection was not. Other sexually transmitted infections were uncommon.
The overall prevalence of having a VMB not dominated by lactobacilli in this population-based cohort of women aged 18–34 years in Amsterdam was high (38.5%), and women of sub-Saharan African descent were significantly more likely to have a polybacterial G. vaginalis-containing VMB than Dutch women independent of modifiable behaviors.
The majority of women of reproductive age have a vaginal microbiota (VMB) dominated by lactobacilli . VMB not dominated by lactobacilli are increasingly being recognized as a cause of adverse reproductive health outcomes, such as increased acquisition and transmission of HIV (reviewed in ) and preterm birth (reviewed in ). The clinical condition known as bacterial vaginosis (BV) is thought to be the most common type of VMB not dominated by lactobacilli [1, 4]. Molecular studies in the last decade have consistently identified the following anaerobes with high relative abundance in BV cases: Gardnerella vaginalis, Atopobium vaginae, BVAB1-3, Mobiluncus species, Prevotella species, Sneathia/Leptotrichia species, Megasphaera species, among others . Other types of VMBs not dominated by lactobacilli, such as VMBs containing a high relative abundance of pathobionts, have also been identified but less commonly . Until recently, many research groups lumped all VMBs not dominated by lactobacilli together into one community state type (CST IV), which was originally described by Ravel et al in 2011 . An expert consultation organized by the U.S. National Institutes of Health (NIH) in 2015 called for more detailed descriptions of the various types of VMBs not dominated by lactobacilli and, eventually, subcategorization into multiple CSTs . This is deemed necessary to improve our understanding of the etiology and pathogenesis of different CSTs and their sequelae, and to develop targeted interventions.
More than a third (38.5%) of the women in our population-based study in Amsterdam had a non-lactobacilli-dominated VMB, of which 83.6% resembled BV and 16.4% had a VMB dominated by Bifidobacteriaceae (not including G. vaginalis), Corynebacterium, or pathobionts. Women of sub-Saharan African descent (either African Surinamese or Ghanaian) were significantly more likely to have a polybacterial G. vaginalis-containing VMB, and African Surinamese women were significantly more likely to have a L. iners-dominated VMB, than Dutch women after controlling for sociodemographic factors, sexual risk behaviors, vaginal cleansing practices, and hormonal contraceptive use.