Check the info on this thread: Mold and Mildew
I think bacteria in the droppings could be an issue as well. Saturating the mess down with the tea tree mixture mentioned in the mold thread & letting it soak in before cleaning it up should help since tea tree is antibacterial & antifungal. (mold killing) The recipe I posted makes a concentrate that you mix with water to use. I posted that I use 3 tablespoons of the concentrate to a quart of water to make a spray. You might want to use more than 3 tablespoons to make it stronger than I stated in the post. The stronger you mix it, the quicker the mixture will separate- be sure to shake OFTEN to remix.
If after the tea tree mixture soaks in it's too wet to clean up easily, dumping plain salt on it will soak up moisture & salt is also antibacterial & antifungal. I know that dumping salt on an egg that has fallen on the floor is the easiest way to clean it up. Then instead of chasing slimy egg all over you can just scoop it up with a dust pan.
Keep in mind that I have never cleaned up after bats nor do I know anybody that has. I'm thinking (typing) out loud here. HTH Blessings ~herbalmom