Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genome analysis sheds light on drug-resistant pathogen

28.03.2003


Mobile DNA’s role in vancomycin resistance of Enterococcus faecalis



‘Jumping’ elements of DNA have enabled the bacterium Enterococcus faecalis to acquire stubborn resistance to a range of antibiotics – including a “drug of last resort” that is used against such bacterial pathogens.

That is one of the conclusions reached by scientists at The Institute for Genomic Research (TIGR), which sequenced and analyzed the complete genome of E. faecalis V583, a strain of the opportunistic pathogen that is resistant to the antibiotic vancomycin. That strain was first isolated at a St. Louis hospital in 1987.


The results of this work, supported by the National Institute of Allergy and Infectious Diseases (NIAID), are published in a paper in this week’s issue of Science.

Ian Paulsen, Ph.D., the TIGR researcher who is the first author of the Science paper, says the genome analysis found that “mobile elements” – small segments of DNA that can jump between organisms or their chromosomes – appear to play an important role in helping the bacterium quickly develop drug resistance.

The TIGR analysis found that nearly a third of the E. faecalis genome – which encompasses more than 3.2 million DNA base pairs – consists of mobile or ‘foreign’ DNA “That’s an unusually high percentage of mobile elements in a microbial genome,” said Paulsen.

Those mobile elements include three plasmids in the bacterium and multiple remnants of phage, plasmids, and other mobile elements, including transposons and a pathogenicity island located on its single chromosome. Scientists identified two sites in the genome that are related to vancomycin resistance or tolerance.

One of those sites, Paulsen said, appears to be a newly-identified vancomycin resistance transposon, carrying vanB resistance genes. A transposon is a mobile element that can “jump” from one part of a chromosome to another, or from a chromosome in one organism to that of another organism – sometimes carrying along genes that encode for drug-resistance. In the case of vanB, the encoded genes allow the bacterium to alter its cell wall structure to prevent vancomycin from damaging it.

“It’s clear that Enterococcus’s ability to acquire mobile elements has significantly contributed to its drug resistance,” says Paulsen. “The vancomycin resistance is found on a mobile element in the genome.”

TIGR’s president and director, Claire M. Fraser, Ph.D., says the deciphered Enterococcus genome will provide an important tool for biomedical researchers. “The identification of a novel vancomycin-resistant transposon in E. faecalis demonstrates the power of genomics to reveal new insights into the biology of important human pathogens,” Fraser says. “This information is critically important in the search for new antibiotics and vaccines to combat infections diseases.”

E. faecalis lives in the gastrointestinal tracts of humans and animals and is often found in soil, sewage, water and food as a result of fecal contamination. While the bacterium is normally symbiotic in the human gut – causing no harm – it can cause serious infections when other tissues are exposed to the bacterium. Those maladies include infective endocarditis, bacteremia, and urinary tract infections.

Physicians often use vancomycin to treat opportunistic E. faecalis infections if other drugs fail to slow their progress. But the growing number of bacterial strains that are resistant to such antibiotics has made it more difficult for physicians to treat those infections effectively.

An even greater concern is that E. faecalis has been found to act as a “reservoir” for vancomycin resistance. Other researchers already have observed how resistance to vancomycin can be transferred from E. faecalis to more aggresively pathogenic bacteria such as Staphylococcus aureus. That transferral of drug resistance has become a major concern for physicians around the globe.


The Institute for Genomic Research (TIGR) is a not-for-profit research institute based in Rockville, Maryland. TIGR, which sequenced the first complete genome of a free-living organism in 1995, has been at the forefront of the genomic revolution since the institute was founded in 1992 and is a leading center for microbial genomics. TIGR conducts research involving the structural, functional, and comparative analysis of genomes and gene products in viruses, bacteria, archaea, and eukaryotes.

Additional Contact:
Ian Paulsen, Ph.D., Assistant Investigator, TIGR
(301) 838-3531 or ipaulsen@tigr.org


Robert Koenig | EurekAlert!
Further information:
http://www.tigr.org/

More articles from Health and Medicine:

nachricht Chances to treat childhood dementia
24.07.2017 | Julius-Maximilians-Universität Würzburg

nachricht World first: Massive thrombosis removed during early pregnancy
20.07.2017 | Universitätsspital Bern

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>