Oh dear, so I am accused of misunderstanding the facts of the study.
A URL to the actual paper would have helped (yes, I do know it was published in PLoS ONE).
But, to quote from the official Weil-Cornell Press Release:
"While it is clear that new MS disease activity requires an environmental trigger, the identity of this trigger has eluded the MS scientific community for decades," Dr. Vartanian says. "Work is underway to test our hypothesis that the environmental trigger for MS lays within the microbiome, the ecosystem of bacteria that populates the gastrointestinal tract and other body habitats of MS patients."
Which suggests that the researchers subscribe to the multi-component theory
I did wonder whether their discovery came under the heading of Environmental or Situational, and the quote makes it quite clear that they see it as the first. So they still have to nail down one of the other two factors before this becomes promising, let alone "extremely promising".
I also note:
The study describes discovery of C. perfringens type B in a 21-year-old woman who was experiencing a flare-up of her MS.
and call to mind the Latin tag Post hoc ergo propter hoc
This may prove to be a critical discovery, or it may just be coincdence - that is what research is all about. Further, this may support the work of Borody (2009), but that in turn rests on the work of Gower-Rousseau et al (2003). So some of the hints have been there for ten years. The relationship remains to be demonstrated, but the Weill-Cornell discovery may have moved things on by two steps rather than just one.