Dr. Brian Carlsen, a Mayo Clinic plastic surgeon and orthopedic hand surgeon, says two-thirds of those hospitalized needed surgery.
It's not that the mouths of cats have more germs than dogs' mouths or people's, it's because of the cat's sharp teeth, Carlson, the study leader, and colleagues say.
"Dogs' teeth are blunter, so they don't tend to penetrate as deeply and they tend to leave a larger wound after they bite. The cats' teeth are sharp and they can penetrate very deeply, they can seed bacteria in the joint and tendon sheaths," Carlsen said in a statement.
"It can be just a pinpoint bite mark that can cause a real problem, because the bacteria get into the tendon sheath or into the joint where they can grow with relative protection from the blood and immune system."
In addition, the bacteria injected by a cat bite can include a strain common in animals that is particularly hard to fight with antibiotics, Carlson says.
The study conducted by Carlson and his colleagues involved 193 Mayo Clinic patients with cat bites to the hand from Jan. 1, 2009, through 2011. Of those, 57 were hospitalized, with the average stay three days.
Of those hospitalized, 38 needed to have their wounds surgically irrigated, or flushed out, and infected tissue removed, Carlson says.
The study, published in the Journal of Hand Surgery, found eight patients needed more than one operation, and some needed reconstructive surgery.
About half of the patients first went to the emergency room, and the others went to primary care. The mean time between the bite and medical care was 27 hours, the study said.
Patients with bites directly over the wrist or any joint in the hand had a higher risk of hospitalization than people with bites over soft tissue, the study said.
Physicians and victims of cat bites to the hand need to take the wounds seriously and carefully evaluate them, Carlsen says. If patients have inflamed skin and swelling, aggressive treatment should be pursued, Carlson said.