'Glow test' for anthrax could speed up bioterror response

Date: Mar-03-2014Researchers at the University of Missouri in the US have proved a "glow test" can

detect the presence of deadly anthrax bacteria in hours instead of the usual days, promising to

significantly cut the time it takes to respond to a potential bioterrorism attack.

Anthrax is not strictly a bacterium, but the disease is caused by the bacterium Bacillus

anthracis, which produces two deadly toxins - lethal toxin and edema toxin.

Recent anthrax research on mice suggests

that death is caused primarily by lethal toxin targeting heart cells and muscle cells

surrounding blood vessels, and edema toxin targeting liver cells.

Although anthrax is a treatable disease, chances of survival are greatly improved if

diagnosis is quick and followed by the right therapy.

Shortly after the 9/11 terror attack in the US in 2001, news outlets and government offices

received mailed letters containing anthrax spores that killed 5 people and infected another 17.

The ensuing clean up and decontamination cost over $3 million.

Now, first responders have tests to screen for dangerous materials in mailed items. In 2001,

no such systems were in place. Yet even today, the test for anthrax agents takes up to 48 hours

to return a result.

But the new test being developed at the University of Missouri (MU) together with the

private company Guild BioSciences of Charleston, SC, might be about to dramatically change that

by identifying the presence of anthrax-causing bacteria within hours.

New test takes only 5 hours to detect anthrax bacteria

George Stewart, professor and medical bacteriologist at MU's Bond Life Sciences Center,

explains:

"Normally to identify whether an organism is present, you have to extract the material,

culture it, and then pick colonies to examine that might turn out to be anthrax bacteria.

Then

you conduct chemical testing which takes some time - a minimum of 24 to 48 hours. Using this

newly-identified method, we can reduce that time to about five hours."

The new method uses a bacteriophage - literally "bacteria eater" - a type of virus that invades

and kills its bacterial host.

By genetically modifying such phages, scientists can exploit their ability to enter bacteria

and do various things, such as send them instructions to trigger cell suicide.

In 2001, no systems for screening dangerous materials in mailed items were in place. Yet even today, the test for anthrax agents takes up to 48 hours to return a result.

David Schofield of Guild BioSciences has engineered a "bioluminescent reporter phage" that

glows when it enters live cells of certain bacteria.

The team at MU tested the new phage against a panel of B. anthracis strains and

found it not only detected the deadly strains effectively, but also dramatically reduced the test

timescale to a few hours. And they found with this method they could also detect even low levels of anthrax bacteria and rule out any false positives.

The phage is highly specific to the deadly anthrax bacteria strains. For example, it failed

to detect members of the closely related Bacillus cereus group and other common

bacterial pathogens.

Another benefit of using the phage is not only can it show if anthrax bacteria are present,

but whether the spores are alive.

Last year, the team reported their work, which is funded by the US Department of Agriculture,

in the Journal of Microbiological Methods.

They now plan to seek federal approval so the test can be produced and distributed, says

Prof. Stewart, who cautions that while there have not been any further bona fide anthrax attacks since

those following 9/11:

"That doesn't mean that it's not going to happen, we just have to be prepared for when it

does occur again."

In the meantime, Medical News Today learned how researchers discovered another voracious predator of anthrax

bacteria in zebras in Namibia. The predator is also a bacteriophage, in this case an

unusually large one called Tsamsa.

Written by Catharine Paddock PhD




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