What do BVAB1, BVAB2 and BVAB3 mean in BV tests?

You may have had a vaginal test result come back that tested positive or negative for the opaquely named ‘BVAB’ species, 1, 2 or 3.

BVAB stands for Bacterial Vaginosis Associated Bacterium

The BVABs are newly discovered bacteria related to or in the Clostridiales order that are highly specific for bacterial vaginosis (BV). Each BVAB is one bacteria, but because these bacteria are still being classified and their genetics being traced to figure out where they fit in, they just get a set of letters and not a real name. The bacteria have been provisionally named using DNA sequencing and matching in DNA libraries.

In one research project of 73 vaginal fluid samples with and without BV, BVAB1 was found in 41 per cent of the samples, BVAB2 was found in 89 per cent of samples, and BVAB in 41 per cent of BV vaginal fluid samples. With information from the DNA libraries, it was found that these three species were highly correlated with bacterial vaginosis.

In two samples where bacterial vaginosis tests were negative, but tests for BVAB came back positive for two types, BV developed within a few months of the tests.

BVAB2 was found in 89 per cent of the fluid samples with BV.

BVAB bacteria is more specific for BV than Atopobium vaginae, which is very highly specific for treatment resistant recurrent BV, though A. vaginae can exist without issue in healthy vaginas.

     References

Molecular Identification of Bacteria Associated with Bacterial Vaginosis, David N. Fredricks, M.D., Tina L. Fiedler, B.S., and Jeanne M. Marrazzo, M.D., M.P.H., November 3, 2005, N Engl J Med 2005; 353:1899-1911, DOI: 10.1056/NEJMoa043802