Finegoldia magna is an anaerobic gram-positive bacteria, previously known as Peptostreptococcus magnus, that can be associated with and contribute to bacterial vaginosis.

This bacteria is normally found in the digestive tract and the urinary and genital tract of humans, but is also found on the skin and in the mouth. F. magna has been implicated in a range of infections, including vulvovaginal and urinary tract infections.

About Finegoldia magna

F. magna is a major anaerobic commensal (native) bacteria in humans, often regarded as a contaminant in blood cultures. F. magna may frequently be overlooked as an opportunistic pathogen, since ‘commensal’ labels mean it is not considered dangerous, despite the fact that it may be in certain areas of the body and in some people.

F. magna can be involved in vaginosis that involves more than one microbe, and is not thought to be the only bacteria to cause an imbalance in the vagina. It needs friends to cause a problem.

F. magna usually appear in groups, with the growth rate in the lab quite slow. F. magna requires an oxygen-free environment to survive, though some cells in contact with air have survived more than 48 hours.

These bacteria produce acetic acid (vinegar) and ammonia, which may account for odours produced when this bacteria colonises the vagina in any meaningful way.

F. magna produce a protein that helps the bacteria adhere to cells and each other. This protein blocks the activity of a human antibacterial peptide, with the protein playing a large role in F. magna’s ability to colonise and survive in a human host. F. magna produce collagenase and gelatinase, enzymes that break down collagen and gelatin respectively.

Another protein produced by F. magna, protein L, enhances colonisation of the vagina and is thought to contribute to bacterial vaginosis.


Marnie E.Rosenthala, Albert D. Rojtmanb, Elliot Franka, Finegoldia magna (formerly Peptostreptococcus magnus): An overlooked etiology for toxic shock syndrome? Medical Hypotheses, Volume 79, Issue 2, August 2012, Pages 138-140