Healthy vaginal conditions depend on a range of factors, and significantly, the balance between the naturally occurring microorganisms and the effects of their combined genome.¹

While microbiomes in other parts of the body such as the gut or skin have a diverse range of microorganisms, there is much less diversity in vaginal microbiota. A spectrum of five core vaginal microbiome types or community state types (CST) have been recognised: four have a predominant Lactobacillus species (L crispatus, L iners, L gasseri, or L jensenii). L acidophilus may be present in low levels but contributes to vaginal health. The remaining CST is a mix of other mainly anaerobic species divided into subgroups with either reduced or no Lactobacillus activity.^2,3,4

Vaginal dysbiosis is an imbalance in this vaginal microbiome (sometimes called the vaginome) with increased diversity or reduced lactobacilli presence. Dysbiosis increases susceptibility to conditions such as bacterial vaginosis (BV), thrush (vulvovaginal candidiasis), urinary tract infections and sexually transmitted diseases. If inflammation is present, then the term vaginitis is appropriate.^4,5,6

The mixed diversity CST may be regarded as a vaginal dysbiosis or even bacterial vaginosis. Other factors associated with dysbiosis include hormonal influences such as menstruation and menopause, ageing, pregnancy, sexual intercourse, and hygiene habits such as douching.^1,7