What started off as a joke between friends became a study published in the Journal of Hospital Infection with a surprising conclusion: Fist-bumping reduces the transmission of bacteria by about four times, compared with shaking hands.

W. Thomas McClellan, a plastic and hand surgeon in Morgantown, West Virginia, was talking with two colleagues about MRSA (methicillin-resistant Staphylococcus aureus), a difficult-to-treat, antibiotic-resistant bacterial infection prevalent in hospitals.

"When you go into a room with a patient with MRSA, you put on a gown and wash your hands," he said. "Meanwhile, the patient's family is there without any of that on, and you go shake their hands, which probably have MRSA on [them]." So McClellan had an inspiration, prompted by how he greets his young kids: "Hey, how about a fist bump?" We asked him to elaborate on the merits of fist-bumping.

Aside from use in hospitals, do you think fist-bumping should be adopted in daily life?

I do. And I'll tell you why. One, MRSA is really rampant in the community. When you go to Whole Foods or something like that, you wipe your cart handle down with an antibacterial cloth. We have alcohol sanitizers in hospitals. Well, that stuff is ineffective against some bacteria. When you think about the kinds of pathogens you are exposed to in the community, it makes a lot of sense to limit your exposure.

What part does hand-washing or hand-sanitizing play in fist-bumping?

You can't fist bump and never wash your hands. The one thing about fist-bumping is that it's not the usable surface of your hand. If you shake someone's hand, you then eat with that part of the hand. Fist-bumping protects that usable surface. You need to wash your hands; you need to limit exposure; and you need to use alcohol sanitizers.

The holiday season is approaching, which means there will be a lot of physical contact—hugging, kissing on the cheeks. Is fist-bumping the safest kind of greeting?

I'm not saying that everyone should be going around fist-bumping, but people should have an awareness of what they're doing. If you're shaking hands and about to sit down for a meal, you should wash your hands. If you have an open wound on your hand, you should definitely be washing your hands more frequently.

Are you planning any related research in the future?

This study did not address viruses. Viruses are much more easily transmitted. I think viruses are much more communicable than bacteria, particularly with the rise of H1N1, bird flu, and other viral pathogens.

Do you fist bump more now?