Check out this April 2025 study linking specific gut bacteria to MS:
Identical twin study – one with MS, one without – same genes, different microbes.
These two stood out: Eisenbergiella tayi and Lachnoclostridium.
When introduced into mice, they triggered MS-like symptoms.

Multiple sclerosis and gut microbiota: Lachnospiraceae from the ileum of MS twins trigger MS-like disease in germfree transgenic mice—An unbiased functional study | PNAS

We developed a two-tiered strategy aiming to identify gut bacteria functionally linked to the development of multiple sclerosis (MS). First,…

www.pnas.org