After using your toilet brush to clean your toilet you can use bleach in a bucket to sanitize and keep the toilet brush clean and sanitary.
After cleaning my toilet using a regular toilet brush I fill a bucket with hot water and then add a cup of bleach to the bucket of water.
Then after cleaning the toilet brush out in the toilet I then put the toilet brush into the bucket of bleach and hot water and let it sit for a few hours and then remove it and place the brush behind the toilet to dry out.
The bleach and hot water will kill off any germs and bacteria that can linger on the brush and keep it smelling good as well.
Hydrogen Peroxide is also another good disinfectant to kill off germs and bacteria that can be on a toilet brush and you can spray your toilet brush with some hydrogen peroxide to keep it sanitary and clean and free of germs and bacteria.