Fannyhessea vaginae is a species of bacteria in the family Atopobiaceae, and the only species in the genus Fannyhessea. It is a facultative anaerobic, Gram-positive rod-shaped or elliptical coccobacillus found as single elements or in pairs or short chains. It is typically isolated from 80% of women with bacterial vaginosis and it is implicated in treatment failures. Invasive infections such as bacteremia have been reported.