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Research on Skin Bacteria Sets New Treatments in Motion

Posted: June 19, 2009

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The NIH study involved taking skin samples from 20 sites on the bodies of 10 healthy volunteers. "We selected skin sites predisposed to certain dermatological disorders in which microbes have long been thought to play a role in disease activity," said study coauthor Maria L. Turner, M.D., senior clinician in NCI's Dermatology Branch.

The researchers extracted DNA from each sample and sequenced the 16S ribosomal RNA genes, which are a type of gene that is specific to bacteria. The researchers identified more than 112,000 bacterial gene sequences, which they then classified and compared. The analysis detected bacteria belonging to 19 different phyla and 205 different genera, with diversity at the species level being much greater than expected.

To gauge how much the skin microbiome differs among healthy people, the researchers studied many different parameters. They found considerable variation in the number of bacteria species at different sites, with the most diversity being seen on the forearm (44 species on average) and the least diversity behind the ear (19 species on average).

The research also generated information that may prove useful in efforts to combat the growing problem of methicillin-resistant Staphylococcus aureus (MRSA), a bacterium that can cause serious, even life-threatening, infections. While it is known that a significant proportion of people have colonies of S. aureus inside their noses, the NIH team checked to see where else on the body surface that these bacteria thrive. They found that the crease of skin outside the nose is the site with the microbial community most similar to that found inside the nose.

"Not only does our work shed new light on understanding an important aspect of skin biology, it provides yet another example of how genomic approaches can be applied to study important problems in biomedical research," said NHGRI's scientific director Eric D. Green, M.D., Ph.D., who is a co-author of the study. "This also demonstrates what can be achieved through efforts that pull together researchers from across NIH."