by Sheela Philomena on  April 27, 2011 at 2:09 PM Research News
 Study Says Some Bacteria 'Go to Sleep' to Hide from Antibiotics
Some bacteria go off grid and hide in order to avoid antibiotic treatments, revealed in a study.

The study, led by Thomas Wood, professor of chemical engineering at the Texas A and M University, details this surreptitious and elaborate survival mechanism of the bacteria.

"Through our research, we're understanding that some bacteria go to 'sleep', and that antibiotics only work on bacteria that are metabolically active," said Wood.

"You need actively growing bacteria to be susceptible to antibiotics. If the bacterium goes to sleep, the antibiotics are not effective because the bacterium is no longer doing the thing that the antibiotic is trying to shut down," he added.

It's an alternative method for survival, said Wood, that starkly contrasts the widely studied genetically based approaches utilized by bacteria through which bacteria gain resistance to antibiotics as the result of mutations experienced throughout time.

Wood and his colleagues found that when encountering oxidative stress, their bacterial cells initiated a process through which an antitoxin called MqsA was degraded, in turn allowing the toxin MqsR to degrade all of the cells' messenger RNA.

This messenger RNA plays a critical intermediate role in the cell's process of manufacturing proteins, so without it the cell can't make proteins.

With the protein-manufacturing factory shut down, the bacterial cell goes dormant, and an antibiotic cannot "lock on" to the cell. When the stressor is removed, the bacterial cells eventually come back online and resume their normal activities, said Wood.

"A small community of bacteria is in a sense hedging its bet against a threat to its survival by taking another approach," he said.

"To the bacteria, this is always a numbers game. In one milliliter you can have a trillion bacterial cells, and they don't always do the same thing under stress, " he said.

"If we can determine that this 'going to sleep' is the dominant mechanism utilized by bacteria, then we can begin to figure out how to 'wake them up' so that they will be more susceptible to the antibiotic. This ideally would include simultaneously applying the antibiotic and a chemical that wakes up the bacteria. That's the goal - a more effective antibiotic," he added.

The study is explained in the online April edition of Nature Chemical Biology.

Source: ANI

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