Welcome to HW. We're sorry to see you need to be here, and as well that your biopsy was unusually rough.
I'm not aware of scar tissue and e-coli. That is the first mention I've seen.
IGRT Radiation can (as it did in my case) aggravate any colo-rectal issues (I had surgery in the past, and my radiation oncologist did have me double checked before starting, but it flared up just the same).