I agree Jorge, you can never truly sterilize anything in the human body. Not for long, anyway.
I think you are correct that the idea is to keep the numbers low, and keep them mostly lacto's (aerobic). They help keep the anaerobes in check.
It's the anaerobes that produce the bulk of toxins. The ammonia, hydrogen sulfide etc. Those toxins are easy to deal with in the lower bowel. You just fart them out. But cause big time oxidative stress in the small bowel.
This also explains why some people get so much relief from probiotics while others feel nothing. If you have too much bacteria in the small bowel, probiotics make you feel better.
I think this is the final concept in getting rid of Candida.