The Evolution of BV Research: A Century's Journey

Bacterial vaginosis has been an unresolved medical problem for over a century, with the vaginal microbiota being revealed as ever more complex as further research is completed^1–3.

BV research all started out with a Dr Döderlein in the 1890s, the guy who discovered lactobacilli. Obviously he named them Döderlein’s bacillus after his fine self, and wrote about their specific features and habitat, being the vagina and gut. He talked about the classic presentation of grey-white discharge and lower levels of vaginal acidity (higher pH) present in BV, and how the bacillus (lactobacilli) weren’t present, but another kind of bacteria in their place.

Döderlein first called the condition leukorrhea, which is now used to simply describe vaginal discharge, not BV discharge. They called it ‘non-specific vaginitis of unknown cause’.

In the mid-50s a couple of guys, Gardner and Duke, said that non-specific vaginitis was caused by a sexually transmitted microbe that they had identified, first as Haemophilus vaginalis, afterwards changing it to Corynebacterium vaginale. Turns out it wasn’t either. It was a whole new genus, Gardnerella, hence the name Gardnerella vaginalis.

Problem with this was, G. vaginalis didn’t fit the bill because it was discovered that half of all women with healthy vaginas, maybe all women, had G. vaginalis present.

In 1983 nonspecific vaginitis was renamed bacterial vaginosis, because once any sexually transmitted infections were removed, there was no inflammation, yet an overgrowth of these gram-negative anaerobes remained.

The Amsel criteria was introduced as the diagnostic standard and on Gram-stains of vaginal fluids. Nugent and friends then made the Gram-stains more specific, giving them a score, called the Nugent Score. The scores were from 1-10, with the score reflecting the shift of bacteria from predominantly lactobacilli to predominantly G. vaginalis and friends⁴.

A grade of 1-3 was negative for G. vaginalis, with the mid-range scores being mixed, and the 7-10 scores meaning predominantly G. vaginalis and other gram-negative anaerobic bacteria.

Nugent scoring is pretty laborious in the clinic, so it is only used at STI clinics with adequate resources and by research studies due to its accuracy. One of the issues with Nugent scores and Amsel scores are that they are unfortunately not very comparable⁵.

There are also other bacteria involved in BV that aren’t really talked about a great deal, as the focus has been on G. vaginalis for many years. These include Mobiluncus spp. and Atopobium vaginae, but there are now hundreds of other BV-related bacteria⁶.

References

Danielson D, Teigen PK, Moi H, ‘The genital econiche: focus on microbiota and bacterial vaginosis’, Annals of the New York Academy of Sciences, Issue: The Evolution of Infectious Agents in Relation to Sex, 2011

1.
Turovskiy Y, Sutyak Noll K, Chikindas ML. The aetiology of bacterial vaginosis. Journal of Applied Microbiology. Published online March 14, 2011:1105-1128. doi:10.1111/j.1365-2672.2011.04977.x
2.
Khedkar R, Pajai S. Bacterial Vaginosis: A Comprehensive Narrative on the Etiology, Clinical Features, and Management Approach. Cureus. Published online November 10, 2022. doi:10.7759/cureus.31314
3.
Abou Chacra L, Fenollar F, Diop K. Bacterial Vaginosis: What Do We Currently Know? Front Cell Infect Microbiol. Published online January 18, 2022. doi:10.3389/fcimb.2021.672429
4.
Mohammadzadeh F, Dolatian M, Jorjani M, Alavi Majd H. Diagnostic Value of Amsel’s Clinical Criteria for Diagnosis of Bacterial Vaginosis. GJHS. Published online October 29, 2014. doi:10.5539/gjhs.v7n3p8
5.
Sood S, Mala R, Kapil A, Gupta S, Singh N. Comparison of Amsel’s criteria with low and high Nugent’s scores for the diagnosis of bacterial vaginosis. Indian J Sex Transm Dis. Published online 2022:56. doi:10.4103/ijstd.ijstd_67_21
6.
Mondal AS, Sharma R, Trivedi N. Bacterial vaginosis: A state of microbial dysbiosis. Medicine in Microecology. Published online June 2023:100082. doi:10.1016/j.medmic.2023.100082