Cholera strain evolves new mechanism for causing disease

Dec 09, 2010

New clinical strains of cholera appear to have evolved a distinctly different mechanism to cause the same disease according to research published in the current issue of the online journal mBio.

Vibrio cholerae is the causative agent for the cholera. While there are more than 200 different serogroups only the O1 and the O139 have been known to cause epidemic and pandemic outbreaks of disease, using a toxin-coregulated pilus (TCP) and cholera toxin (CT), which other strains lack.

"While non-O1, non-O139 strains have caused sporadic disease globally, the virulence mechanisms are not fully understood, since most of these strains lack TCP and CT," say the researchers from Harvard Medical School and the International Center for Diarrhoeal Research in Dhaka, Bangladesh.

The researchers studied a newly identified non-O1, non-O139 strain of the bacteria called AM-19226. Using comparative genomics, they investigated how this new strain causes diarrhea.

Many require something called a type III secretion system (T3SS) in order to cause disease. In previous studies, the researchers discovered a T3SS and identified a protein (vopF) that they believe could be involved in causing disease.

In the current study they identified an additional protein (vopE) and using mouse models show that AM-19226 requires T3SS to cause and that both vopE and vopF contribute to the disease.

"With the discovery of the T3SS in V. cholerae and its role in the virulence of non-O1 and non-O139 strains, it is astonishing to observe how this has evolved two independent pathogenic mechanisms to cause similar disease," say the researchers.

Explore further: New knowledge about host-virus coevolution unmasked from the genomic record

More information: mbio.asm.org/

Provided by American Society for Microbiology

not rated yet
add to favorites email to friend print save as pdf

Related Stories

The tiny difference in the genes of bacteria

Jun 30, 2009

Every year, diarrhea causes around five million fatalities worldwide. Most people die due to pathogenic microorganisms, such as bacteria or viruses, which were ingested into the gastro-intestinal tract through contaminated ...

Disease-causing Escherichia coli: 'I will survive'

Sep 09, 2009

Strains of Escherichia coli bacteria that cause food poisoning have been shown to have marked differences in the numbers of genes they carry compared to laboratory strains of E. coli. Some of these genes may enable them t ...

Designing probiotics that ambush gut pathogens

Sep 08, 2009

Researchers in Australia are developing diversionary tactics to fool disease-causing bacteria in the gut. Many bacteria, including those responsible for major gut infections, such as cholera, produce toxins that damage human ...

Recommended for you

Devising a way to count proteins as they group

8 hours ago

A new study from Indiana University-Purdue University Indianapolis and University of California Berkeley researchers reports on an innovative theoretical methodology to solve "the counting problem," which is key to understanding ...

Mysteries of 'molecular machines' revealed

8 hours ago

"Inside each cell in our bodies and inside every bacterium and virus are tiny but complex protein molecules that synthesize chemicals, replicate genetic material, turn each other on and off, and transport ...

Bacteria are wishing you a Merry Xmas

14 hours ago

A bacterium has been used to wish people a Merry Xmas. Grown by Dr Munehiro Asally, an Assistant Professor at the University of Warwick, the letters used to spell MERRY XMAS are made of Bacillus subtilis, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.