Clostridioides difficile can become pathogenic and potentially fatal when its population proliferates unchecked in the gut microbiome, often after antibiotic use.

“when you take an antibiotic that's essentially almost like a nuclear bomb to your microbiome it kills everything in there um but in some cases it doesn't kill everything and so there are these strains of Clum defil that after you take an antibiotic it's killed all the different strains off but it didn't kill your Clum a cell strain and the problem with killing off all the other strains is now all the competition is gone so you imagine you know you have all these this ecosystem and different microbes and now you've just gotten rid of all of them so now you have this strain that has no competition and can start to propagate unchecked and so it's when you start to have these really high levels of this strain cicil in your microbiome that's when it starts to make you really sick and actually ultimately it's fatal”