The fist bump isn't just President Obama's trademark greeting; it's also the healthier choice.

According to a new study published in the American Journal of Infection Control, a fist bump transmits 1/20th of the amount of bacteria that a handshake does. Compare that to the high-five, which spreads about half the amount of germs spread through a handshake. (The longer or firmer a handshake, the more germs transmitted.)

To test the amount of germs transmitted, researchers immersed a sterile-gloved hand into a container of E. coli bacteria, and, once dry, shook hands, high-fived, or fist bumped another sterile-gloved recipient hand. The researchers then examined the number of bacteria transferred.

In a statement, the study's author David Whitworth of Aberystwyth University in the United Kingdom encouraged the use of the fist bump, as people will never adopt a no-contact greeting:

Adoption of the fist bump as a greeting could substantially reduce the transmission of infectious diseases between individuals... It is unlikely that a no-contact greeting could supplant the handshake; however, for the sake of improving public health we encourage further adoption of the fist bump as a simple, free, and more hygienic alternative to the handshake.

Researchers also dipped the gloves in paint to observe the surface area covered by the hands and, as expected, found that handshakes exposed the most area to the recipient.

Besides being a cleaner alternative to the classic handshake, a fist bump could be the start of the end of healthcare-associated infections, which are some of the leading causes of preventable harm and death in the United States. 

But Mary Lou Manning, an associate professor in the school of nursing at Thomas Jefferson University and president-elect of the Association of Professionals in Infection Control and Epidemiology, told USA Today the study won't be enough to push fist bump usage on mots people. Instead, she said, the more hygienic strategy would be to encourage hand-washing. 

Whitworth admitted to USA Today that Manning was correct, and that because prominent figures like President Obama use fist bumps and high fives, people have continued to use hand-to-hand contact as a greeting. But, he said, "I couldn't imagine the British prime minister doing that."

Well, Mr. Whitworth: 

President Obama high-fives British Prime Minister David Cameron. (REUTERS/Paul Hackett)

Here's hoping next time they fist-bump instead.