Article Text

Original article
A fruitful alliance: the synergy between Atopobium vaginae and Gardnerella vaginalis in bacterial vaginosis-associated biofilm
  1. Liselotte Hardy1,2,3,
  2. Vicky Jespers1,
  3. Said Abdellati3,
  4. Irith De Baetselier3,
  5. Lambert Mwambarangwe4,
  6. Viateur Musengamana4,
  7. Janneke van de Wijgert4,5,
  8. Mario Vaneechoutte2,
  9. Tania Crucitti3
  1. 1HIV and Sexual Health Group, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
  2. 2Laboratory Bacteriology Research, Faculty of Medicine & Health Sciences, University of Ghent, Ghent, Belgium
  3. 3STI Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
  4. 4Rinda Ubuzima, Kigali, Rwanda
  5. 5Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
  1. Correspondence to Liselotte Hardy, Institute of Tropical Medicine, Nationalestraat 155, Antwerp 2000, Belgium; liselotte.hardy{at}


Objectives Bacterial vaginosis (BV) is characterised by a change in the microbial composition of the vagina. The BV-associated organisms outnumber the health-associated Lactobacillus species and form a polymicrobial biofilm on the vaginal epithelium, possibly explaining the difficulties with antibiotic treatment. A better understanding of vaginal biofilm with emphasis on Atopobium vaginae and Gardnerella vaginalis may contribute to a better diagnosis and treatment of BV.

Methods To this purpose, we evaluated the association between the presence of both bacteria by fluorescence in situ hybridisation (FISH) and BV by Nugent scoring in 463 vaginal slides of 120 participants participating in a clinical trial in Rwanda.

Results A bacterial biofilm was detected in half of the samples using a universal bacterial probe. The biofilm contained A. vaginae in 54.1% and G. vaginalis in 82.0% of the samples. A. vaginae was accompanied by G. vaginalis in 99.5% of samples. The odds of having a Nugent score above 4 were increased for samples with dispersed G. vaginalis and/or A. vaginae present (OR 4.5; CI 2 to 10.3). The probability of having a high Nugent score was even higher when a combination of adherent G. vaginalis and dispersed A. vaginae was visualised (OR 75.6; CI 13.3 to 429.5) and highest when both bacteria were part of the biofilm (OR 119; CI 39.9 to 360.8).

Conclusions Our study, although not comprehensive at studying the polymicrobial biofilm in BV, provided a strong indication towards the importance of A. vaginae and the symbiosis of A. vaginae and G. vaginalis in this biofilm.

Trial registration number NCT01796613.


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Supplementary materials

  • Abstract in Dutch

    This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.


  • Handling editor Jackie A Cassell

  • Contributors All authors were involved in the main study that generated the data. For the present study, LH wrote the first draft of the manuscript. VJ, TC, MV and JvdW revised and edited the text. IDB, TC, LH, VJ and JvdW created the experimental design. SA, LM, VM and LH performed the testing and VJ and LH performed the data analysis. All authors revised and approved the present version of the manuscript.

  • Funding This work has been funded by The European & Developing Countries Clinical Trials Partnership (EDCTP) through a project entitled ‘Preparing for clinical trials with vaginal rings that protect women from HIV and unintended pregnancy’ (grant code SP.2011.41304.043); the University of Liverpool and the ITM.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The Ring Plus study was approved by the Rwanda National Ethics Committee, Rwanda (Approval number 481/RNEC/2013); the ethics committees of the Institute of Tropical Medicine (ITM), Belgium (Approval number 864/13); the Antwerp University Hospital, Belgium (Approval number 13/7/85) and the University of Liverpool, UK (Approval number RETG000639IREC).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement The database relevant to the study has been made available to all collaborators.