Common ER treatment of dog and cat bites includes lots of wound irrigation with saline, tap water, or betadine/water mix, bacitracin ointment and gauze dressing. Generally no suturing of the wound, cuz it is already infected and you want it to drain easily. Lots of docs use a dose of iv antibiotics and send you home with ten days worth of one of the penicillin family- Bacteria tnd to be pretty temperature specific in their living conditions, so everything in a human's mouth thrives at 98.6 F and infects wounds pretty effectively. Dog and cat oral flora are happy at 104 F; soil bacteria usually like it cooler, submarine volcanic vent bacteria like it warmer. The other infection-realted issue, mentioned by several folks already, is that bites are puncture wounds and crush injuries, too-so the tissue surrounding the wound is less able to mount an effective immune response. edit: dogs spend too much time licking their parts to be effective wound cleaners, imho.

Side note: vets and kennel attendants deal with biting dogs bu using animal snares (http://animal-traps.com/catch-poles.htm). The old man made his about 28" long of 1/2 inch galvanized pipe with a T fitting on end. An aircraft cable loop extended through the pipe and out the T, and could be adusted by pulling on the loop on the other end. Once you snare 'em, you can keep the dog at distance, and help him relax by making calm and soothing mouth noises while applying firm pressure to the neck by tightening the noose. Edit: sturdy pipe snare can also be used as an impact tranquilizer prior to snaring the dog.

other side note: for statistics on dog homicides and how lawyers manage bad dogs, see http://www.dogbitelaw.com/PAGES/danger.htm#homicides.