I found some important evidence during my experiments. I thought this would be of interest to this forum.
The point of the experiment is to find a growth medium for isolating my "parasites".
One medium included using the probiotic BioK. The strains were acidophilus and L. Casei.
These are actually very long rod bacteria--look like little worms---anyway, it was a failure.
I later discovered that the medium had a PH of around 4.5 This is quite acidic, and could not sustain my guys, which need PH of > 7.
So, in conclusion, it would seem the upper gut bacteria may have PH altering properties toward the acidic end. Shroom