B. Subtilis will destroy more bacteria than candida, just by the number of bacteria present in the colon. Bacteria contain substances that the body strobglyvreacts to and that dramatically increase inflammation in the body - LPS (lipopolysaccharides) and LTA (lipoteicoic acid). Beyond those two, there are many other substances released.
The Portal vein flows from the colon to the liver, not the reverse direction.