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: Bacterial immune system has a better memory than expected

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

Researchers develop new model of cellular movement

2 hours ago

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

22 hours ago

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

Rapid and accurate mRNA detection in plant tissues

23 hours ago

Gene expression is the process whereby the genetic information of DNA is used to manufacture functional products, such as proteins, which have numerous different functions in living organisms. Messenger RNA (mRNA) serves ...

User comments : 0

More news stories

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.