Yes, for the brushes. Try using a mild dishwashing liquid and water. Rinse well and make sure the bristles are allowed to air dry. If the brush is of good quality, you could wash it every week. If not, the bristles will probably start falling out.
As far as sponges go, you can wash a sponge, but it's easy for bacteria to grow in the inside of a sponge. It must be a sponge that will dry rather quickly. If not, bacteria would have a place to multiply. You can buy disposable spongy cosmetic applicators if you want to be safe.
The best way to keep bacteria from growing in your brushes and sponges is to use Mineral Makeup powder instead of liquid foundation. True mineral makeup does not allow bacteria to grow in it. You still need to wash your brushes, but not as often as you would need to with liquid makeup.