Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cross talk between bacteria, host leads to E. coli infection

01.07.2003


A strain of E. coli that causes severe, sometimes deadly, intestinal problems relies on signals from beneficial human bacteria and a stress hormone to infect human cells, a researcher at UT Southwestern Medical Center at Dallas has discovered.



The finding, which will appear online today in Proceedings of the National Academy of Sciences, could lead to the development of beta blockers as a therapy to impede this cellular signaling system, causing the harmful bacteria to pass blindly through the digestive tract, said Dr. Vanessa Sperandio, lead author of the study.

"You’re not really attacking the bacteria per se," said Dr. Sperandio, assistant professor of microbiology at UT Southwestern. "You are just rendering it blind. The bacteria won’t activate the virulent genes unless it knows where it is. If it can’t activate the things it needs to bind to the intestine, it will be washed away."


In the past, beta blockers have been used to treat migraines, high blood pressure, glaucoma and tremors but not to impede infection. Developing new therapies for infection with this strain of E. coli – known as enterohemorrhagic Escherichia coli, or EHEC – is important because treatment with conventional antibiotics can cause the release of more toxins and may worsen the disease outcome.

Dr. Sperandio found that when a person ingests EHEC, the bacteria travel blindly through the digestive tract until reaching the intestine, where friendly bacterial flora in the intestine and the human hormone epinephrine, or adrenaline, send cellular signals alerting the bacteria to its location. This cellular cross talk leads to a cascade of genetic activations in which the EHEC colonizes the intestine and translocates toxins into human cells, altering the makeup of the cells and robbing the body of nutrients.

"The bacteria gets what it wants – nourishment - and the person ends up getting diarrhea," Dr. Sperandio said.

EHEC is responsible for outbreaks throughout the world of bloody diarrhea and hemolytic uremic syndrome – a condition that can lead to renal failure and death. Severe symptoms are most common in children, the elderly and immune-suppressed people.

EHEC is commonly transmitted through contaminated food or water. Foods known to have caused human infections include raw meat and unwashed vegetables. The Centers for Disease Control and Prevention report 73,000 cases of EHEC infection annually in the United States, resulting in 61 deaths.

Bloody diarrhea typically lasts about a week after infection with E. coli. One week after the condition resolves, some patients may develop hemolytic uremic syndrome, which is characterized by gastrointestinal bleeding, reduced urine production and anemia.

Treating EHEC infection with conventional antibiotics has shown to increase the chances that a patient will develop hemolytic uremic syndrome, Dr. Sperandio said. In 2000, an EHEC outbreak in Scotland affected thousands of people. Half of those infected received antibiotics, and half received no therapy. Of those treated with antibiotics, 18 percent developed the syndrome; of those receiving no treatment, only 5 percent developed the syndrome.

Dr. Sperandio, a Brazilian native whose studies focus mainly on gene regulation, began this three-and-a-half-year study during a postdoctoral fellowship at the University of Maryland School of Medicine. Other authors of the study included University of Maryland researchers.


The work was funded in part by the National Institutes of Health.

Rachel Horton | EurekAlert!
Further information:
http://www.swmed.edu/

More articles from Health and Medicine:

nachricht Electrical 'switch' in brain's capillary network monitors activity and controls blood flow
27.03.2017 | Larner College of Medicine at the University of Vermont

nachricht Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Electrical 'switch' in brain's capillary network monitors activity and controls blood flow

27.03.2017 | Health and Medicine

Clock stars: Astrocytes keep time for brain, behavior

27.03.2017 | Life Sciences

Sun's impact on climate change quantified for first time

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>