Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Advance in cholera bacteria points to new treatment and vaccine

09.12.2005


Opening a new door to an effective vaccine and therapy for a disease that strikes thousands annually, researchers at Dartmouth Medical School discovered that the bacteria that causes the intestinal disease Cholera spreads in the environment in much the same way it infects humans. Appearing in the December 8 issue of the journal Nature, the study investigates the bacterium Vibrio cholerae and its ability to attach to a host, enabling it to multiply and adding to the risk of infecting humans.



"We’ve discovered, through genetics, a factor that is important in the normal biology of the organism out in the environment and it is also one of the very initial factors for cholera colonization in the intestine," said Dr. Ronald Taylor, professor of microbiology and immunology at DMS who led the research. "Now that we know what the bacterium attaches to in the intestine, we can find ways to block that initial contact."

Cholera and the bacterium that causes it is found in contaminated drinking water and food, often in underdeveloped countries and refugee camps. Once the disease takes hold, it causes diarrhea, vomiting, severe dehydration and can result in death if treatment is not promptly given. In 2001 alone, 28 countries reported over 40 outbreaks of cholera to the World Health Organization, resulting in the deaths of thousands.


Large outbreaks are often traced back to contaminated water supplies that are commonly associated with algal or zooplankton blooms. For the V. cholerae bacterium to infect someone with cholera, the bacterium often binds to plankton in the aquatic environment before it arrives at the human intestine via contaminated food and water sources. V. cholerae attaches to the outer surface of plankton, made up of a carbonate substance called chitin. Once attached to the plankton’s chitin, the bacterium thrives on the carbon and multiplies. Humans do not have chitin in the surface of intestinal cells, where the bacterium takes hold, and researchers have been searching for another substance that could be responsible for playing a role in attachment.

In the study, Taylor and colleagues screened cultured intestinal cells and found mutant bacteria that had trouble binding to the intestinal cells. One mutant strain of V. cholerae lacks a gene that enables it to properly bind with a sugar called GlcNAc. When they compared it with normal, wild-type V. cholerae bacteria, the researchers found that the protein encoded by this gene provided normal bacteria the ability to attach to the GlcNAc on cells. The team verified that the GlcNAc in the intestine initiates the attachment and colonization of the bacteria by testing the mutant strain on zooplankton and cultured intestinal cells in vitro as well as in an in vivo cholera model.

"We set out to find factors that would reduce the bacteria’s ability to bind to the epithelial lining of the intestine," said Taylor. "What’s interesting is that we’ve identified a factor that works both in the environment and in the human body. This type of link hasn’t been discussed before and it has a strong potential for vaccine and therapeutic development."

These findings could lead to a new form of therapy to treat people with cholera. "Now that we know that the bacteria are binding this particular sugar, we could essentially trick the infecting bacteria to bind to the sugar included in a derivative of oral rehydration therapy solution instead of the intestine," said study co-author Brooke Jude, a fourth-year PhD student at Dartmouth Medical School.

A vaccine for cholera already exists, but only works 50% of the time and people who take it are only immune for 12 months, according to Taylor. Taylor believes that a more effective vaccine could be developed by inducing the production of antibodies directed against the protein his research team has discovered, thereby blocking its function. This would inhibit an early step in the intestinal colonization process, and the bacteria would pass harmlessly through the body. The authors acknowledge that in addition to GlcNAc, there may be other points of attachment that could still be responsible for allowing the bacteria to bind to the intestine, and they are currently focusing their research to identify any other areas of attachment..

"There may be more of these factors and as we find them and knock them out, we’ll decrease the ability for cholera bacteria to colonize even further," said Taylor.

Andrew Nordhoff | EurekAlert!
Further information:
http://www.dartmouth.edu

More articles from Health and Medicine:

nachricht Malaria Already Endemic in the Mediterranean by the Roman Period
27.07.2017 | Universität Zürich

nachricht Serious children’s infections also spreading in Switzerland
26.07.2017 | 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: Physicists Design Ultrafocused Pulses

Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.

Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | 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

 
Latest News

Programming cells with computer-like logic

27.07.2017 | Life Sciences

Identified the component that allows a lethal bacteria to spread resistance to antibiotics

27.07.2017 | Life Sciences

Malaria Already Endemic in the Mediterranean by the Roman Period

27.07.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>