Photomicrograph of bacteria stained with a dye.
Credit: Muntasir Alam, University of Dhaka
SYDNEY: Small molecules that interrupt communication between bacteria may provide an alternative to antibiotics, says a new study.
Published in the journal Molecular Cell, the study shows that disrupting 'quorum sensing' – or the way bacteria communicate collective information, such as population density, can stop bacteria from killing a host organism.
Significantly, the experts behind the find claim that resistance is less likely to evolve against drugs using this than with those based on conventional antibiotics.
Cutting the channels of communication
“Our results make a strong case and provide compelling evidence that an anti-quorum-sensing strategy is a valid alternative to traditional antibiotics and that there is merit to pursuing [this],” said lead researcher Bonnie Bassler, a molecular biologist from Princeton University in New Jersey, USA.
During communication, bacteria use chemical signals called autoinducers to send messages to receptors located on other bacteria. Bassler and her coworkers suspected that by interfering with these messages by blocking receptors they could create a potent new weapon against bacterial infection.
This is because virulence – or a bacteria's ability to cause illness – is a collective action. One bacterium producing a toxic substance can do little damage, however 100,000 bacteria producing a toxic substance can be fatal.
To test this hypothesis, the researchers showed that a class of small molecules known to block receptors on the outside of bacteria can also stop a key autoinducer from binding to 'LuxR', a quorum-sensing receptor located on the inside of bacteria. This was a promising, if surprising result – LuxR is not evolutionarily related to previously tested receptors.
Spreading the good news
They then put these molecules to the test against a real bacterial infection, using them to treat nematode worms. This stopped the worms dying from infection by Chromobacterium violaceum, a bacteria which also infects humans.
This is good news. Antibiotics, the current treatment of choice, work by stopping bacteria from growing. Resistance readily evolves against these drugs, causing them to have a relatively short useful lifetime. Drugs that block communication, however, might be more difficult to develop resistance to.
Nicolas Barraud, a bacteriologist from the University of New South Wales in Sydney, commended the study.
“This is very exciting work,” he said. “Using combined systematic screening and rational design, new drugs were discovered that can inhibit bacterial killing in worm models, but are not antibiotics. Instead, these are small molecules that effectively interfere with the bacterial communication system, rendering the microbes inoffensive.”
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alternative to antibiotics still have the same result?
If the new drugs effectively interrupt the communication between bacteria so they cannot proliferate, fine, but what about good bacteria? What is the difference between antibiotics that destroy your good bacteria (which you need to live) along with the bad, and a drug that keeps your good bateria from mulitplying?
So go ahead, spend more money on this wasteful research to come up with something that is no better than antibiotics and worse for the distraction and resources taken away from research that is actually life promoting.
When do we actually get to progress in medicine? When do we start to base our health care on wellness instead of sickness? When we stop treating it as a business for profit.
bacteria and their ability to survive ..
Need less to mention about the intelligence bacteria posses, and also their updates, probably more than our scientists. Their capacity to stay undisturbed,and thrive is again a nature's gift to them.
Who knows how the effect may turn adverse on host cells to create
worst possible diseases than even cancer.. let us play safe..
Talluri Vijai Kumar