You’re a Walking, Talking, Bad-breath-having Bacterial Colony

The revelation the we’re not alone is always a little shocking. No, we don’t mean that aliens exist. Instead, we’re referring to the fact that even when no one else is in the room, you’re not all by yourself. In fact, every second of the day, you play host to trillions – you read that right, trillions – of bacteria. They give you bad breath and tooth decay, they cause your ear infections, they help you digest food.

And they’re legion.

Study: Body is coated with bacteria, inside and out

A recently completed project puts this issue into perspective. In a massive investigation funded by the National Institutes of Health, researchers from 80 different institutions got together to identify (and map the genes of) all the bacteria living on or in the human body. All of them.

Now, after taking samples from 242 volunteers and recording 3.5 trillion genetic base pairs, scientists think they’ve reached a number. So take a guess: How many different species of bacteria do you think are crawling around you right now – 100? 500? 750?

Try 10,000.

The results of the investigation, which is called the Human Microbiome Project (HMP), indicated that the average person is host for (to use the word literally) a myriad of microorganic strains.

But how many are in the mouth?

As the researchers themselves noted, different regions of the body have different microbial counts. For instance, in some participants’ GI tracts, scientists could count the number of bacterial strains on one hand. Yet in other regions, like the mouth, the numbers are much higher.

Unfortunately, the HMP results don’t yet specify how many different species are hiding out in your mouth. But we looked elsewhere, and dug up the answer.

Probably the most thorough count of oral bacteria yet published can be found in a 2003 issue of the Journal of Clinical Microbiology. Its authors, who hail from the University of Michigan, Ann Arbor, and the Forsyth Institute, used genetic sequencing (similar to the HMP’s method) to tally the number of species found in the mouths of people with and without bad breath.

What researchers found is that, while people who brush or use specialty breath fresheners tend to harbor fewer species, the typical mouth supports about 600 separate strains of microbes.

And that’s just the number of species – the total number of individual bacteria living in your mouth right now is in the tens of billions! No wonder bad breath is so common.


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