There are normally about 500 different strains of bacteria in a healthy human gut. When they flora is wiped out by antibiotics, taking probiotics only gives you a few different strains. If you gt a stool transplantation, you get hundreds of different species to repopulate the gut, to bring it back to a healthy flora.
In this Mayo Clinic article, they recommend stool implantation for serious C. Difficile colitis:
[
www.mayoclinic.com]
Here's an article which discusses the procedure in depth:
[
en.wikipedia.org]