Because it doesn't happen to most people, we as a society tend to underestimate how potentially harmful a course of even a mild antibiotic can be - wiping out a portion of the healthy strains and suppressing much of the rest gives other microbes, sometimes incredibly harmful ones, an excellent opportunity to take over. And sometimes, this sticks with you for years and years, and becomes impossible to root out as the organisms adapt to their new place better.
Regrettably, C.Diff is somewhat exceptional in that cure rates of FMT alone are incredible(90%+), while most other microbiome-linked conditions - IBS, Ulcerative Colitis, SIBO, and all kinds of assorted stuff like many cases of chronic fatigue or depression - often get no or very temporary benefit.
My own experience with DIY FMT was that I experienced 1-2 days of complete relief(brainfog, depression, anhedonia, mild diarrhea), and 3-4w of feeling much better, before symptoms returned in almost-full-force. Many other people have had even less luck- most actual successes involve comprehensive antibiotic pretreatment to get rid of existing microbes, and many repeat transplants, before the benefits stick.
Nonetheless, this is a step in a good direction, and will hopefully open doors to further research for other conditions - far, far too many people are forced to deal with severe illness while doctors shrug and funnel everyone into psychiatry for their "psychosomatic symptoms"
*my observations support this.
I recently had occasion to get some dental work done, pulling a tooth and replacing it with a titanium implant. Part of the prep for that exercise included taking a strong antibiotic before the tooth removal so that the likelihood of bacteria around the gums causing a major infection is minimal.
I haven't seen a doctor for anything for a while and after reading the data sheet for the prescribed antibiotic I was considering backing out of the whole deal since one potential consequence was that the antibiotic could zap all the bacteria except the much more resistant, more persistent C. diff which could then begin raging and possibly cause more problems than I would've had by keeping the tooth.
Several members of my family have careers as medical professionals so I contacted one of them that I trust to be a no-bullshit source of information. They are a nurse with decades of experience. I described the situation and told them that I was considering scratching the tooth implant since I didn't want to chance any health issues related to antibiotic side effects, especially a C Diff infection.
They told me that the likelihood of a bad outcome could be decreased significantly if you follow a simple procedure involving combining probiotics with the antibiotic in the dosing schedule.
It was recommended that I buy a probiotic with a lot of beneficial bacteria from several species (I chose a store brand with 20 billion beneficial bacteria). The dose schedule was easy - One hour before taking each dose of the antibiotic, just take one capsule of the probiotic.
I followed that probiotic one hour before antibiotic dosing schedule and have to say that I am now in a much better place than I was before the dental visits.
For several years after my last doctor visit, where I was prescribed an antibiotic to deal with a persistent sinus infection, I have had progressively worse digestive issues to the point where it was becoming normal for me to have indigestion or reflux severe enough to compel me to take a Tums antacid up to four times a week to deal with the problem. My whole digestive system was out of kilter in ways I won't describe here but it was simply not fun to be me.
Since beginning this probiotic/antibiotic pretreatment to head off post-op infection related to the implant procedure I have seen a near-total reversal of fortune. It has been nearly two months and I have not had a single instance where I felt that I needed an antacid. It felt like flipping a switch. I went from an increasing dependence on antacids before bedtime to a near-total elimination of acid reflux or sour stomach. I hated that I was having trouble eating foods that I loved because those foods had become triggers for acid reflux. Since completing this probiotic/antibiotic schedule I have taken to eating all of those trigger foods and have had no ill effects at all. Truly like finding out that the light at the end of the tunnel really was just another sun-shiney day and not an oncoming locomotive. It is obvious in several ways that other issues downstream from the stomach have also normalized and for the first time in years I feel like the bottom part of the tubulars are working up to spec.
I just wanted to put that out there for others who may find themselves needing a course of antibiotics. Unfortunately oral antibiotics are the go-to prescription on many doctor visits and several can cause digestive issues since they zap all the gut biota on their way to the exit leaving the user open to infection or colonization by bacteria that are hard to kill, like C Diff, so that the user ends up with part of their biology in worse health than before their visit.
Remember folks, buy a probiotic with a huge number of several species of beneficial bacteria. One hour before taking each dose of the antibiotic, take a probiotic. For each antibiotic pill, take one probiotic pill. I took mine (the pro and the anti) with food and water at each dose, typically a slice of cheese and a tortilla with a large glass of water.
I had such great results that I am still taking the probiotic once daily.
Good luck.