Dr. Julie Segre: I work as part of the Human Microbiome Project, which is a new initiative
funded by the NIH Common Fund. For almost 20 years now, I have been a researcher working
in a laboratory, but this was a new opportunity to really work with physicians and microbiologists
and laboratory scientists and all come together to form a group to ask a very simple but important
question, which is, "What are the bacteria that live on our body and how do they contribute
to our health and to disease states?" Well, the question is old: What are the bacteria
that live on body? And for a long time, we've answered that question by seeing what we could
culture and what would grow when we put them on bacterial plates like this. So, for a long
time, we would look under the microscope and say, "Oh, Staph epidermidis is the dominant
bacteria that lives in your skin." Well, this project is exploration, what we have found
by not just looking at what we can culture but what we can actually
sequence. It's like you go in with a microscope and at first, if you didn't have a very powerful
lens, you'd look and you'd be able to see, you know, maybe some of the larger pieces
of -- when you look under a microscope, you could see a hair or something like that.
But when we go in with this more powerful microscope of looking at the DNA sequence
of every bacteria that's there, suddenly we see this enormous diversity.
We find Staph epidermidis; it's not that what you learned in the text books isn't true,
it's just that there is an entire ecosystem of bacteria that live there, many of which
are really hard to culture and they don't grow very well on these petri dishes that
we have because that's not what they've evolved to do. They've evolved to live on our skin,
and they eat, you know, the dead parts of our skin, but what do they do for us? Like,
why would we want to have these bacteria living on our skin? Well, they then take some of
these oils that our skin cells produce and they turn it into a natural moisturizing.
We're really trying to think about what are the healthy bacteria that live on our skin
and to really focus on those healthy bacteria. Now, there are bacteria that come in and cause
infections, and so I'm not saying that we shouldn't worry about bacteria getting onto
our skin. And, you know, not just as a scientist but as a mother of two young kids, I believe
very strongly in hand washing and I hope my kids wash their hands every time they come
in from the playground, but we have to lose this language of warfare and thinking about
bacteria as only pathogenic. Bacteria in the gut aid in digestion, bacteria on the skin
aid in keeping your skin moist and moisturized and supple, and if you have a very, you know,
smooth skin, then you don't have cracks in your skin where bad bacteria could get in.
And the good bacteria -- what we call the commensal bacterias -- are also basically
holding the property on your skin. And so, if a good bacteria is standing there, occupying
that space, the good bacteria is going, "I'm here. I'm here. Don't even try, you know,
to sit down here. And, you know, I'm here and I'm providing a benefit to this person,
and this person does not want you living on their skin, so get out of here." And that's
sort of the difference between the transient bacteria
that you wash off your hands and the ones that take up residence on your skin. So, what
is the exploration? Well, the exploration is about how does a microbial shift or the
small microorganisms, these bacteria -- how does a bacterial shift contribute to disease
states and then how do you bring that back into balance to achieve health again? And
what we're learning about this is also just changing the way we think about ourselves.
What we've found was that in healthy volunteers, the skin is an ecosystem. And what that means
is that the bacteria that live here on my chest are really different than the bacteria
that live here in my underarm or really different than the bacteria that live here in the bend
of my elbow. Well, of course. I mean, here is a sweaty area with large hair follicles,
and here is a moist area that has, you know, really no hair; when you sweat, that's a waste
product of bacteria. And, you know, why do areas that you sweat in, you know, smell bad?
And why does your underarm smell different than your, you know, your feet, the bottom
of your foot, your sneaker? Because these are different areas that sweat and they do
have different types of ecosystems of bacteria. What I've seen is that people now are using
all these antimicrobial products and, you know, we just -- I -- we don't know how that's
going to change the bacteria that live on our skin and how that's affecting the good
bacteria and the bad bacteria. And what we know is a whole history of when you wash your
hands, you wash off all of the transient bacteria, but, you know, the bacteria that live on our
body are not necessarily bad, and we should treat them with a little bit more respect.