October 2, 2013



Maggie: Bacteria can be found nearly everywhere – inside of rocks, in the deepest part of the ocean, and even all over you. So, to figure out what these germs are all about, I went to a lab in California that studies bacteria. And, yes, you are about to see some of mine.

At this very moment, there are over 100 trillion cells of bacteria living all over you!

Professor Justin Sonnenburg: Those microbial cells actually outnumber our human cells by tenfold. So, by cell number, we are actually more microbial than we are human.

Maggie: That is right! You are more bacteria then, well, you! Alright, alright. You can calm down. All this bacteria, often referred to as your microbiota or your microbial community, might actually be a good thing.

In his lab at Stanford, Professor Justin Sonnenburg and students like Jessica Ferrera get up close and personal with all of these germs.

Jessica Ferrera: I used to think that they were really scary, but as I worked with them more and more, I realized that they’re really not that scary at all.

Maggie: So, just to clarify. Bacteria can look really funky and smell really disgusting but it doesn’t mean that all bacteria is bad for you.

Jessica: Definitely.

Maggie: Today, many leading scientists are trying to reverse bacteria’s bad rep. They say our ongoing war against germs could be making us sicker.

Dr. Sonnenburg: There is actually mounting evidence that this overuse of sanitizers is actually resulting in less microbes that we are exposed to. There may be a link between this reduced exposure and a lot of Western diseases – asthma, allergies, certain types of cancer.

Maggie: Even obesity has been linked to an overly disinfected lifestyle. We battle germs with anti-bacterial soap, hand sanitizers and – perhaps most damaging – antibiotics. All this germ killing can even lead to what is known as a superbug, a new, stronger bacteria that can’t be treated with the old methods. So, while things like antibiotics are beneficial and necessary, too many can hurt the balance of bacteria in your body.

Dr. Sonnenburg: Immediately after you take oral antibiotics, your gut microbiota suffers. And it takes months for those microbes to grow back. And we don’t really know if that microbial community, after antibiotic treatment, ever returns to the exact same state that it was before the antibiotic treatment.

Maggie: So why do scientists care so much about making sure our bodies stay germy? Ninety percent of your bacteria lives in your gut. And as a trade-off for giving them a home, bacteria helps us out by breaking down nutrients from food.

Dr. Sonnenburg: One of the most important things that this microbial community can do for us is help us digest foods that we can’t digest on our own.

Maggie: Scientists are so excited about this give-and-take relationship, known as symbiosis, because unlike other aspects of our health, our gut microbiota is something we actually have control over.

Dr. Sonnenburg: When we’re born, we’re born into this world as a sterile being. We actually have no microbes associated with us. For the first year of our life, we’re actually being colonized by microbes from the environment.

Maggie: Things like the food you eat, if you have a pet and where you live, all create and change your microbial community. To study these changes, Dr. Sonnenburg takes human bacteria and puts it in a mouse.

Dr. Sonnenburg: These mice live in these sterile plastic bubbles, and so they have no microbes associated with their bodies. And so, we can actually take a germ-free mouse that has no microbes in its intestine and we can colonize them with microbes derived from the human digestive tract and study human microbes inside the mouse. So, we could create a Justin mouse colonized with Justin microbes.

Maggie: And a Maggie mouse?

Dr. Sonnenburg: And a Maggie mouse colonized with Maggie microbes, and learn how our microbiotas respond differently to these different types of foods.

Maggie: There is no Maggie mouse just yet but I was able to roll up my sleeves and offer up some germs from the Channel One News team for science.

Testing both my hand…

I am transferring Maggie hand bacteria to this petri dish.


Oh, we are getting crazy with bacteria!

…And some samples from the man behind the camera.

This better grow more than mine – that is all that I am saying!

After three days, our bacteria samples looked…well…nasty. But luckily, Justin says we both have great microbial diversity.

To learn more about your bacterial best friends, just check out my blog post over at


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