Senior author Michael Otto, Ph.D., of NIH's National Institute of Allergy and Infectious Diseases, says these findings illustrate at the molecular level how MRSA epidemics may emerge and spread. Moreover, their study identifies a potential target for novel therapeutics.
MRSA is a leading cause of severe infections that occur predominantly in hospitals. MRSA epidemics happen in waves, with old clones of MRSA bacteria disappearing and new clones emerging, a process whose molecular underpinnings are not fully understood.
Previous data indicated that the sasX gene is extremely rare. Therefore, the researchers were surprised when they analyzed 807 patient samples of invasive S. aureus taken over the past decade from three Chinese hospitals. Their data showed that sasX is more prevalent in MRSA strains from China than previously thought, and the gene's frequency is increasing significantly: From 2003 to 2011, the percentage of MRSA samples containing sasX almost doubled, from 21 to 39 percent.
This finding suggests that the sasX gene is involved in molecular processes that help MRSA spread and cause disease. The researchers determined in laboratory and mouse studies that sasX helps bacteria to colonize in the nose, cause skin abscesses and lung disease, and evade human immune defenses. Further, the scientists say their work provides additional evidence for a long-held theory that the emergence of new clones of highly virulent MRSA bacteria occurs through horizontal gene transfer, the exchange of DNA between different strains. Notably, the sasX gene is embedded in a so-called mobile genetic element, a DNA segment that can transfer easily between strains.
Most sasX-positive samples found in the study were from the ST239 group, the predominant MRSA lineage in China and large parts of Asia. However, because the scientists have already observed the transfer of sasX to MRSA clones other than those belonging to the ST239 group, Dr. Otto and his team predict that the frequency of sasX will increase internationally. They plan to both monitor its spread and work to develop therapeutics to prevent MRSA strains expressing sasX from colonizing and infecting people.
Min Li, Ph.D., associate professor at Fudan University in Shanghai, a former postdoctoral fellow in Dr. Otto's laboratory, designed the study. Other collaborators are from the University of California, San Francisco.
NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov/.
NIH...Turning Discovery Into Health
Ken Pekoc | EurekAlert!
Purdue cancer identity technology makes it easier to find a tumor's 'address'
16.11.2018 | Purdue University
Microgel powder fights infection and helps wounds heal
14.11.2018 | Michigan Technological University
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences