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.