The methods by which some bacteria survive when exposed to antibiotics have been uncovered by scientists.
Researchers Yuichi Wakamoto of the University of Tokyo, Japan, and Neeraj Dhar of the Swiss Federal Institute of Technology in Lausanne, Switzerland, say their discovery could prove useful in the creation of drugs that target hard-to-treat bacterial strains, including drug-resistant TB.
Their study, published in today’s edition of Science focuses on Mycobacterium smegmatis, which is related to the microbe that causes TB, and its response to the TB drug isoniazid.
Although recent studies have demonstrated that some bacteria survive exposure to antibiotics thanks to a population of non-dividing "persister cells", Wakamoto, Dhar and colleagues have shown that non-dividing persister cells are not responsible for M. smegmatis’s survival when it is exposed to isoniazid.
They have shown that cell survival is linked to random pulses of a bacterial enzyme called KatG, which allows some cells to survive antibiotic treatment.
Their study found that individual cells produced KatG in random pulses that determined the cell’s chances of survival and were not correlated with their growth rates.
“Our Science paper provides clear experimental proof that other mechanisms of persistence also exist,” said Dhar. “Our findings necessitate the re-examination of the mechanisms of persistence at the single-cell level in other bacteria, including Mycobacterium tuberculosis, which causes TB in humans.”
Science 4 January 2012
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