Study: 80M bacteria exchanged during 10-sec kiss

By DrBicuspid Staff

November 26, 2014 -- What's in a kiss? About 80 million bacteria, the amount that is normally exchanged during a 10-second "French" kiss, according to a new study of smooching couples by Dutch researchers (Microbiome, November 17, 2014).

Intimate kissing involving full tongue contact and saliva exchange appears to be an adaptive courtship behavior unique to humankind and is common in more than 90% of known cultures, the authors noted.

The more you tongue-kiss, the more alike the collection of bacteria in your saliva becomes to that of your partner, according to the study.

"Tongue-kissing is a nice example of brief exposure to a gigantic quantity of bacteria. Around 80 million in just 10 seconds," principal investigator Remco Kort said in a statement. Kort is a microbiologist and principal scientist at the Netherlands Organization for Applied Scientific Research (TNO) and a professor of microbial genomics at Vrije University Amsterdam.

The research was a collaboration between TNO and the Micropia museum in Amsterdam.

"A number of these [bacteria] nestle on your tongue but many don't," Kort said. "We wanted to find out the extent to which the oral microbiota -- the sum of the micro-organisms you have in your mouth -- are similar in the two partners."

The study used Next Generation Sequencing technology to identify the oral microbiota of 21 couples who completed questionnaires on their kissing behavior, including average intimate kiss frequency.

The researchers found that the oral flora on the tongue of the partners seem to be much more alike than the oral flora of random persons. The kissing behavior did not seem to have much of an effect: A tongue kiss did not lead to an increase in the similarity in micro-organisms between the tongues of both partners.

"It didn't matter whether the partners said they tongue-kissed nine times a day or nine times a year," Kort noted. "Obviously there are other key factors at work, such as having the same diet or using the same toothpaste."

In the saliva, however, there was a clearly discernible effect: The more often you tongue-kiss each other, the more alike the collection of bacteria in your saliva becomes.

It's possible to swap up to 500 different species of germs, including those that cause periodontal disease, from the holiday tradition of kissing under the mistletoe, according to the Academy of General Dentistry (AGD).

"With just one kiss, this infection can be passed between couples and even to children," AGD spokesperson Lawrence Bailey, DDS, has said. "In the spirit of the season, folks with gum disease should refrain from kissing under the mistletoe."

Red wine shows antimicrobial effects on oral bacteria
European researchers have found that red wine and its inherent components display antimicrobial effects on oral bacteria biofilms, according to a new...
Study: Periodontal bacteria may cause heart disease
The same bacteria that cause periodontitis also promote heart disease, according to a study presented at the American Society for Microbiology meeting....
Bacteria in 1,000-year-old plaque similar to current oral bacteria
An international team of experts has discovered disease-causing bacteria in a German Medieval population that are the same or very similar to inflammatory...
Oral bacteria create ethnic 'fingerprint'
The bacteria in the human mouth -- especially those under the gums -- are as powerful as a fingerprint at identifying a person's ethnicity, according...
No mistletoe kisses for perio patients
The holidays offer dentists another opportunity to warn patients about the consequences of candy and soda overdoses -- but exchanging kisses underneath...

Copyright © 2014

Last Updated np 2/20/2015 12:30:08 PM