Prevotella spp. in the vagina and mouth

Prevotella is a gram-negative bacterial genus, a common microbe that can be part of the commensal (normal) mouth and vaginal flora. Prevotella can be involved in anaerobic infections in the respiratory tract (lungs, nose, throat, ear)​1​.

Periodontal (gum) disease and abscesses are commonly associated with Prevotella spp.

Prevotella may be implicated in bacterial vaginosis that appears to originate from oral sex or via saliva used as lube in the vagina. This transmission route is by no means obvious since the vagina can easily contain these bacteria as a natural component. Dentists have had an ongoing fight with Prevotella species.

Prevotella is been found in mouth wounds, bites, urinary tract infections, abscesses in the brain, bone inflammation (osteomyelitis), bacterial or fungal nail infections (paronychia), and bacterial infections found in the blood (bacteraemia).

Some populations have Prevotella species abundant in the intestine, while others show no sign. Diet is the presumed culprit there, with those eating a lot of protein and animal fats having more Bacteroides bacteria, and those with a carb-heavy diet having more Prevotella species.

About Prevotella

Prevotella are present in animals and humans, with human infection being based on opportunity.

Prevotella strains are gram-negative, non-motile, rod-shaped single cells that operate best in anaerobic conditions. Prevotella colonises by binding to other bacteria and epithelial cells, which can exacerbate an existing infection with other bacteria. 

Prevotella species take on different forms in their life cycle, and some can form biofilms, which may be of mixed species.

Prevotella antibiotic resistance

Prevotella is naturally antibiotic-resistant (genetically), which means this species does not respond very well to antibiotic therapy, though it is known (at least at the moment)to respond to metronidazole, moxicillin/clavulanate, ureidopenicillins, carbapenems, cephalosporins, clindamycin, and chloramphenicol.

Prevotella generally uses a fermentative method of metabolism, with some species requiring vitamin K and heme (in blood) to survive. There is an association with β-Lactamase activity, with some species resistant to β-lactam antibiotics.

Some antibiotic treatments can actually make Prevotella infections worse, for example, aminoglycosides, trimethoprim/sulfamethoxazole, and quinolones. Prevotella can produce collagenase, neuraminidase, deoxyribonuclease, heparinase and proteases.

Where Prevotella colonises

Prevotella exists on most mucosal surfaces – mouth, gut, urinary tract and vagina. Anything oxygen-deprived is a target, which is why wounds and tissue with little blood supply is a favourite.

Prevotella intermedia is a biofilm-creating species which also enjoys a higher pH (more basic) with ideal temperatures sitting at between 34 and 36˚C.

Prevotella tends to proliferate during times of increased hormone production too, particularly during pregnancy and puberty/adolescence.

In the vagina, Prevotella species are found about 50 per cent of the time, with common species in healthy women including P. oralis, P. bivia, P. disiens, P. oris and P. buccae.

Some species of Prevotella can cause respiratory problems – chronic ear infections, chronic sinusitis, pneumonia, abscesses in the lungs, and neck lymph node infections.

Prevotella species

Twenty species of Prevotella cause infection, typically presenting as periodontitis, abscesses, bacterial infections of the blood, infection of wounds, and infection in the genital tract. 

Bacteroides melaninogenicus was turned into two new classified species: Prevotella melaninogenica and Prevotella intermedia.

There are 29 known species of Prevotella:

  1. Prevotella albensis
  2. Prevotella amnii
  3. Prevotella bergensis
  4. Prevotella bivia
  5. Prevotella brevis
  6. Prevotella bryantii
  7. Prevotella buccae
  8. Prevotella buccalis
  9. Prevotella copri
  10. Prevotella dentalis
  11. Prevotella denticola
  12. Prevotella disiens
  13. Prevotella histicola
  14. Prevotella intermedia
  15. Prevotella maculosa
  16. Prevotella marshii
  17. Prevotella melaninogenica
  18. Prevotella micans
  19. Prevotella multiformis
  20. Prevotella nigrescens
  21. Prevotella oralis
  22. Prevotella oris
  23. Prevotella oulorum
  24. Prevotella pallens
  25. Prevotella salivae
  26. Prevotella stercorea
  27. Prevotella tannerae
  28. Prevotella timonensis
  29. Prevotella veroralis


  1. 1.
    Baron S. Medical Microbiology. Published online January 1, 1996.

Jessica Lloyd - Vulvovaginal Specialist Naturopathic Practitioner, BHSc(N)

Jessica is a degree-qualified naturopath (BHSc) specialising in vulvovaginal health and disease, based in Melbourne, Australia.

Jessica is the owner and lead naturopath of My Vagina, and is a member of the:

  • International Society for the Study of Vulvovaginal Disease (ISSVD)
  • International Society for the Study of Women's Sexual Health (ISSWSH)
  • National Vulvodynia Association (NVA) Australia
  • New Zealand Vulvovaginal Society (ANZVS)
  • Australian Traditional Medicine Society (ATMS)