Via the Wall Street Journal, "Burning Question: Can Kissing Your Dog Make You Sick?"
The last paragraph is important- I think there is this kind of pervasive old wives' tale that dog saliva can help prevent infection, which is why dogs are always licking their wounds.
Not true! Dog mouths (like human mouths) are chock-full of bacteria, and keeping bacteria away from open wounds is one of the most important aspects of dog (or cat) first aid. Small wounds often need only minimal treatment (clip fur, clean thoroughly) as long as the pets are prevented from licking them and introducing bacteria to the wound. Keep your e-collars around!