The risk of infection after dog and cat bites ranges from 3 to 18% for dog bites to 28 to 80% for cat bites. Whereas most cat bites are deep puncture wounds, many dog bites cause open lacerations.
Large observational studies and limited clinical trials suggest that after high-pressure irrigation of the wound, it is safe to close most bite wounds (even on the extremities) up to 12 hours after injury (healing by primary intention).
However, human bites that are sustained over the metacarpophalangeal joints (“clenched-fist bites”) are especially prone to infection and require aggressive irrigation and treatment with antibiotics and should not be closed with sutures.
New England Journal of Medicine - Vol. 359, No. 10, September 4, 2008