Scientists uncover how superbug Staph aureus resists our natural defenses

Mar 24, 2008
Scientists uncover how superbug Staph aureus resists our natural defenses
Dr. Ferric Fang and his colleagues at the UW have uncovered the mechanisms through which the bacteria Staph aureus, seen here in clusters under an electron microscope, can protect itself against our body's natural defenses. Fang's research was featured on the cover of Science magazine on March 21.

Researchers at the University of Washington have uncovered how the bacterium Staphylococcus aureus, including the notorious MRSA (methicillin-resistant Staph aureus) “superbug” strains, resists our body's natural defenses against infection. The work, which was featured on the cover of the March 21 issue of Science, could lead to new ways to fight the bacteria.

Dr. Ferric Fang, UW professor of laboratory medicine and microbiology, and his UW colleagues Dr. Anthony Richardson and Dr. Stephen Libby set out to determine what makes Staph aureus a better pathogen than other bacteria.

They focused on a chemical compound called nitric oxide (NO), a natural antibiotic that our cells excrete to protect us from pathogens. For most bacteria, NO creates an environment that keeps invading microbes from undergoing respiration or fermentation, vital chemical processes that allow bacteria to grow.

The researchers found that Staph aureus has a mechanism that allows it to produce lactic acid in the presence of NO, which allows it to maintain its chemical balance and keep growing and thriving in the harsh host environment. When Staph aureus is exposed to NO, it produces the novel enzyme responsible for lactic acid production, along with another enzyme that converts NO to non-toxic products. NO is commonly found in the nose and nasal passages, and is meant to protect people against disease-causing microbes. But Staph aureus is commonly found in the nose despite the presence of NO, the researchers explained.

When the researchers modified Staph aureus to take away its ability to make lactic acid, the bacteria could no longer tolerate NO. The modified bacteria also lost their ability to survive in host immune cells and cause lethal disease in mice.

"MRSA has become an enormous public health problem, by causing both hospital- and community-acquired infections," explained Fang. "Staph aureus has already colonized about one-third of the world's population, so traditional antibiotics will probably not be the complete answer to the MRSA problem."

However, the researchers added, trying to make Staph aureus more susceptible to our natural defenses might lead to new strategies to de-colonize the population and prevent staphylococcal infections.

Source: University of Washington

Explore further: Scientist discovers populations of rare songbird in surprising new habitat

add to favorites email to friend print save as pdf

Related Stories

Researchers discover key link in a deadly staph bacteria

Nov 15, 2012

(—A new study from Stanford's Department of Chemistry reveals that the cell wall structure of Staphylococcus aureus, a bacterium responsible for a broad range of diseases, depends on growth stage ...

Recommended for you

Literature searches benefit from location tagging

8 minutes ago

Agricultural Research Service ecologist Jason Karl is creating new options for helping researchers to conduct literature searches that go beyond using traditional search terms such as keywords or authors. ...

Himalayan Viagra fuels caterpillar fungus gold rush

14 hours ago

Overwhelmed by speculators trying to cash-in on a prized medicinal fungus known as Himalayan Viagra, two isolated Tibetan communities have managed to do at the local level what world leaders often fail to ...

Science casts light on sex in the orchard

16 hours ago

Persimmons are among the small club of plants with separate sexes—individual trees are either male or female. Now scientists at the University of California, Davis, and Kyoto University in Japan have discovered ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 24, 2008
We already have a few perfectly good remedies for MRSA
infection, they just aren't patentable hence there's no big
money in it. I speak from first hand experience. MRSA nearly killed me and now I am getting well again using colloidal silver, which I used to think was snake oil. Nothing the AMA doctors did (including IV Vancomycin) helped for more than a month or two before the problems resurfaced, but now I am finally beating this problem.
not rated yet Mar 24, 2008
"I am getting well again using colloidal silver..."

Is that the stuff that can turn you blue if you take too much?
not rated yet Mar 24, 2008
Anecdotal reports of individual success do not constitute a repudiation of the mass of statistical data. I'm glad you're getting better. Now, find some real data and show applicability.
not rated yet Mar 25, 2008
RE:Dolsen .. get a clue, patents= $$$$$$$ for pharmaceutical companies, colloidal silver is NOT patentable .. thus it as a competing product. Like open source software vs proprietary they are doing their best to stamp it out.

Oh and "anecdotal reports" include a 6000 year history of use, as well as mainstream use in the USA from 1900 to 1940, check it out.

ALSO if you do a Google search for the following keywords "colloidal silver staphylococcal infection works" you'll get about 105,000 hits, if you substitute 'worthless' for 'works' you get about 800 .. that's all the proof I need. .. oh and yeah if you take (drink) it for years, you will turn slate blue, permanently. There are no serious side effects other than that, compared to the list of side effects from many antibiotics ... blue isn't so bad.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.