Hello, Thomas. Very good point in your post, and I’m glad you asked the question.
All bacteria feed on both inulin and FOS because both are fibers. So of course inulin feeds the bacteria Klebsiella just the same as it does the beneficial bacteria. But this doesn’t say that it’s going to cause a dangerous overgrowth of Klebsiella or any pathogen. And if it does, then we’d all better stop eating vegetables, avocados, and oat bran as well as all the other healthy foods that feed our flora, because they’re all feeding the bad bacteria as well since they all contain naturally occurring FOS and inulin.
What a lot of research does is to overlook one fact; that is, what takes place in a Petri dish doesn’t necessary occur in the human body. Yes, Klebsiella can be placed in a Petri dish and given inulin and it will eat and grow, but in the human intestines the Klebsiella are competing for food and space with the trillions of beneficial bacteria we hope we have in our system as well.
In addition, and this is important, the beneficial bacteria we have are capable of producing acids which are dangerous to and can destroy such pathogens as Klebsiella but not the beneficial flora.
So yes, Klebsiella feed on inulin, but that fact doesn’t mean it’s going to grow out of control anymore than eating a salad does.