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!
Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin
Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy