As the World's Germs

Since we're not really sure, biologically speaking, of what constitutes intelligence, how do we know for sure that other organisms don't have their own?

Think about a group of bacteria living on your skin. They eat and reproduce and all that. When we wash them off our hands, that's a lot like the earth having a flood that washes some of us away. When we have an allergic reaction to something that we come in contact with, isn't that a lot like an earthquake or a hurricane?

Just something fun to think about.