Scientists Take Navel-Gazing to New Level08/05/11
FRIDAY, Aug. 5 (HealthDay News) -- Germs used to be viewed as
only bad, but scientists who have taken navel-gazing to a new level
are finding that the ones living in your belly button coexist quite
nicely with the rest of your body's microbes.
Setting out to dispel the notion that all skin bacteria cause
disease, researchers from North Carolina State University swabbed
the navels of 391 volunteers from across the country, sequenced the
DNA from each sample and published photos of the cultures
anonymously online on the Bellybutton Bacteria Culture database
Preliminary results, scheduled to be presented Aug. 12 at the
Ecological Society of America's annual meeting in Austin, Texas,
revealed similarities in navel bacteria among family members and a
wide diversity of microbes present in any given person.
"The overall concept is compelling," said Dr. Bruce Hirsch, an attending physician in infectious diseases at North Shore University Hospital in Manhasset, N.Y. "When I grew up, germs were bad. But the vast majority of the time, they're good or neutral," he said.
"I think of the human body as more of a forest than a tree," added Hirsch, who was not involved in the study. "Bacteria are a normal part of health, and each human body has more bacteria cells than human cells."
The Bellybutton Bacteria Culture database has become one of the
most watched citizen-science projects in the nation, the study
authors said, with about 55,000 visitors to the website in just
three months. The rate of voluntary participation at sampling
events shot up from 17 percent to 80 percent when passers-by were
informed of the project's purpose.
The researchers chose to sample belly button bacteria because
the area is generally protected from excretions, soaps and
ultraviolet ray exposure. They also felt it would generate
excitement about the study from participants, whose gender, ethnic
background, age and hygienic habits were recorded. More than 80
percent of the samples were viable in cell culture dishes.
Hirsch noted that the results of the study -- which are a work
in progress and have not undergone peer review -- are not detailed
and did not yield many conclusions. But he said most bacteria are
good "and their very presence crowds out more dangerous
"I'm amazed at how the body responds to infection and how often we see spectacular successes in the way it responds," he said. "The human body is incredible. When we look at it from a bacterial perspective, it's like a new world."
Philip M. Tierno Jr., author of
The Secret Life of Germs and director of clinical
microbiology and immunology at NYU Langone Medical Center, said
it's not news to him that there's a greater diversity of bacteria
on the skin than many people think.
The number and types of microbes found in belly buttons may not
be representative of what's found on the rest of the human body
because of its depth, where lint and other "cellular debris" can
accumulate, said Tierno, also a clinical professor of microbiology
and pathology at New York University School of Medicine.
"Only 10 percent of you is you, which should give you an idea of how important microbes are," he said. "Ninety percent is bacteria or microbial cells, although body cells are bigger."
The University of Maryland Medical Center has more information
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