Biological 'timer' helps bacteria survive antibiotics
In a finding that explains the failure of antibiotics to treat several diseases, scientists have found another way bacteria escapes this.
Sensing the time of the drug delivery, bacteria can go dormant for a certain period to evade the stress caused by antibiotics, says a study.
"The finding could lead to the development and greater use of drugs that can maintain constant levels in the body," said the researchers.
The ability of micro-organisms to overcome antibiotic treatments is one of the top concerns of modern medicine.
Using the quantitative approach of physicists, the team, led by professor Nathalie Q. Balaban from the Hebrew University of Jerusalem in Israel developed experimental tools to measure precisely the bacterial response to antibiotics, and developed a mathematical model of the process.
The model led them to hypothesise that a daily three-hour dose would enable the bacteria to predict delivery of the drug, and go dormant for that period in order to survive.
To test their hypothesis, the researchers delivered antibiotics to bacterial populations in the lab for precisely three hours each day.
After only 10 days, researchers found that when exposed to these repeated cycles of antibiotic treatments, the bacteria evolved an adaptation to the duration of the antibiotic stress by remaining dormant for the treatment period.
It showed for the first time that bacteria can develop a biological timer to survive antibiotic exposure.
To further test their hypothesis, the researchers delivered antibiotics for different periods, exposing three different bacteria populations to repeated daily antibiotic exposures lasting 3, 5, or 8 hours.
Remarkably, each of the populations adapted by prolonging their dormant stage to match the exposure duration.
The findings appeared in the journal Nature.
(Posted on 01-07-2014)