Genomic Sequencing Finds Unexpected Bacterial Diversity on Human Skin

EPISODE #22
Uploaded:  July 30, 2009
Running Time:  5:08

SCHMALFELDT:  From the National Institutes of Health in Bethesda, Maryland, this is CLINICAL CENTER RADIO.  Look at your forearm right now.  If you are a typical person, you are looking at 44 different species of bacteria. In fact, you have a wider diversity of bacteria on your skin than you may realize. Grossed out?  Don't be.

MURRAY:  You shouldn't eliminate those organisms.  When you disrupt that population, that's when you have problems.

SCHMALFELDT:  That was Dr. Patrick Murray, chief of the Clinical Center's Department of Laboratory Medicine's Microbiology Service, talking about a recent NIH study looking at the skin's microbiome - that's the DNA or genomes of all the microbes on human skin.  Dr. Murray talked about what researchers have learned from the study.

MURRAY:  I think what it is doing is it is first helping us rethink our concept of the normal bacteria that live on each individual. It is a very complex picture that picture is going to change depending where on the body you do your sampling. We just focus on skin and we look at 20 different skin sites and we found that the types of bacteria and the numbers of bacteria change based on the site that was sampled. The same observations have been made in other parts of the human microbiome project where they have looked at say the mouth or the GI tract or the female genital tract and have seen that again depending on where you are sampling it can be quite a complex different picture. So I think that is one thing, we are learning and we will continue to learn over the next year or two which organisms are part of the normal population that's there, and then what we will be doing is comparing that population, that normal population, with disease that has localized to those areas. So the work that is being done with dermatology, looking at different types of infections like atopic dermatitis or psoriasis, where it involves very specific areas of the skin. We will be able to compare the population of bacteria that is in the diseased state with the population that is in the healthy individual and I think that will help us to understand more the pathogenesis of different types of diseases.

SCHMALFELDT:  The study was launched as part of the NIH Roadmap for Medical Research in order to discover what kind of microbial communities exist in different parts of the body and explore how these populations change with disease.  Using modern DNA sequencing techniques and computer analysis, research teams from the National Human Genome Research Institute, the National Cancer Institute and the NIH Clinical Center found a far more diverse population of microbes on human skin than had been detected previously by growing microbial samples in the lab.  Dr. Murray said there were some interesting revelations for those in the microbiology field in this study.

MURRAY:  What you find out and maybe not too surprising but a bit embarrassing for microbiologists like myself, is that what we do is not very efficient where as I may be able to grow two or three or four different species of bacteria there are maybe ten fold more organisms that are there that I am missing and that is what the genomic techniques were able to show us.

SCHMALFELDT:  Dr. Murray said the study was yet another example of the way different disciplines come together at the NIH Clinical Center, each adding their knowledge and expertise in the search for medical advances.

MURRAY:  I think one of the things that really impressed me when I started working here at the NIH, but in particular with this project, is the ability for different disciplines, in this case different institutes, scientists from different institutes, to get together and look at a problem from a variety perspectives and be able to add their own special knowledge and the whole is really much more than what any of the individual components could be.

SCHMALFELDT:  For more information about the Human Microbiome Project, log on to the NHGRI site at http://genome.gov.  And to find out more about the NIH Clinical Center, including news about the medical research going on here every day, log on to http://clinicalcenter.nih.gov. From America's Clinical Research Hospital, this has been CLINICAL CENTER RADIO.  In Bethesda, Maryland, I'm Bill Schmalfeldt at the National Institutes of Health, an agency of the United States Department of Health and Human Services.

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