Gardnerella vaginalis, which is detected in women both with and without bacterial vaginosis (BV), is acquired through sexual activity and exists in both commensal and pathogenic clades, according to a new study in the Journal of Infectious Diseases.
BV (diagnosed as a Nugent score (NS) >7) is extremely common and responds poorly to treatment, meaning that many women experience a relapse within a year. Gardnerella is almost always present in women with BV and might have a role as a founder organism. However, as it is also present in many women without BV, its precise role remains uncertain. The study aimed to investigate whether Gardnerella exists in both commensal and pathogenic clades and particularly focused on women who have sex with women (WSW) in whom G. vaginalis clade distribution data are lacking and to investigate its association with sexual behaviours.
Nonpregnant premenopausal women (n = 101) who reported a female sexual partner (FSP) in the past 18 months were enrolled. Overall, G. vaginalis was detected in 184/372 specimens (49%) and varied by NS: 130/306 with NS = 0–3 (42%), 15/18 with NS = 4–6 (83%) and 39/48 specimens with Nugent-BV (81%). G. vaginalis detection was associated with self-reported symptoms, NS = 4–6 and Nugent-BV, as well as with Lactobacillus-deficient vaginal microbiota, smoking, history of penile–vaginal sex and frequent sex. Detection of clades 1, 2 and 3 and communities containing ≥2 clades were associated with BV. Interestingly, specific clades were associated with specific sexual behaviours: clade 1 with an increased number of recent sexual partners and smoking, and clade 2 with penile–vaginal sex and sharing sex toys with female partners.
These data suggest that G. vaginalis is sexually transferred and that different clades might have different levels of pathogenicity. Thus, treating sexual partners could help to improve cure rates in women with BV.
Plummer, E. L. et al. Gardnerella vaginalis clade distribution is associated with behavioural practices and Nugent score in women who have sex with women. J. Infect. Dis. https://doi.org/10.1093/infdis/jiz474 (2019)
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Fenner, A. Gardnerella clade associated with sexual behaviours. Nat Rev Urol 16, 640 (2019). https://doi.org/10.1038/s41585-019-0247-6