Diagnosis"I was bit by a cat".
"Kitty kitty kitty here nice kitty kitty, damn it, it bit me in the hand." Often in the space between the thumb and first finger.
When tested by 16S ribosome methodology the wounds are filled with difficult to grow anaerobes, that, when grown, are ampicillin susceptible (Pubmed).
Amoxicillin-clavulanic acid for prophylaxis, for real infections use real antibiotics directed against the flora of the cat mouth. Ampicillin or third generation cephalosporins PLUS metronidazole would be good choices. If PCN allergic use a quinolone PLUS (clindamycin OR metronidazole) OR doxycycline alone. Pasteurella are usually resistant to first generation cephalosporins.
Debride, then prophylaxis for 10 days. And don't forget the tetanus booster. You did, didn't you? Soft tissue infections (cellulitis or abscess) is iv until afebrile, then po for a total of 10-14 days. Septic arthritis or tenosynovitis is 2 -3 weeks of iv. Osteomyelitis is usually 6 weeks of iv.
Cats teeth are like needles and inject bacteria deep into tissue. This makes debridement difficult if not impossible and makes joint infections likely. They say that Pasteurella infections start in the first 48 hours after the bite and that staphylococcal and mixed infections take longer to manifest.
The majority of patients after a scratch will have symptoms of Bartonella (fatigue, arthralgias and myalgias), half of patients will seroconvert and maybe a quarter will have evidence of a blood stream infection (PubMed).
Cats really are vermin that serve no useful purpose but to spread disease. And. Some epidemiologic data suggest cat scratches and bites increase the risk of depression (PubMed). I'd be depressed if I had to own a cat.
Raw cat food is the source of ESBL producing Enterobacteriaceae in cat shit. And cats do lick their butts before they bite you. So there is more than toxoplasma in that litter box. (PubMed). As an aside, cat shit is way over rated as a source of toxoplasmosis. It's mostly from undercooked meat.
Relevant links to my Medscape blog