With bites you need to consider not only the ton of different bacteria inhabiting the mouth of whatever/whoever was the biter, but also the flora of whatever part of the body was bitten. Mouths tend to be a schmogourbord of Gram positives and negative, aerobes and anaerobes. The two bugs to specifically keep in mind when thinking about bites are Eikenella in human bites and Pasturella in animal bites (especially cat bites).
Amox-clav is a fairly good choice for bites (of both the human and animal variety) but you need to remember that if the bite if say, on the ear, you’ll also need coverage for pseudomonas. To make matters a little more confusing Eikenella is resistant to clindamycin, macrolides, metronidazole, and fluoroquinolones. So if the bitten person is allergic to penicillins, clindamycin just won’t do.