My medicine team almost resorted to it for a refractory case last year. Poor man was s/p esophageal surgery, and ended up being NPO almost 2 months. No results with Flagyl, Vanc (per J-tube), and we seriously began looking to other alternatives.
Apparently, Turkish yogurt (Kefir) is another last-ditch solution. The bacteria in it are able to colonize the gut, and it occasionally works. Unfortunately, the guy didn't have any family to track it down, and we weren't allowed to give it, even if we could find it.
We did discuss the stool transplant - and decided that again, since he had no immediate family, the pharmacy would have to rise to the occasion, as it were.
Thankfully, the last course of vanc+flagyll finally worked.