By Akari Miki
Every time scientists develop and implement a new antibiotic, a strain of resistant bacteria appears immediately, countering doctors’ efforts to cure common infections. How resistance to antibiotics evolves rapidly has been largely unknown, but recent research by biophysicists at the Hebrew University of Jerusalem has been a large step toward solving this mystery. In their experiment, the researchers exposed bacterial populations to antibiotics in cycles until a resistant strain appeared, and they monitored the evolution of the bacteria throughout the process. In the beginning, they observed the quick emergence of bacteria that could survive the antibiotic by hibernating and suspending growth during the treatment. After dormancy, this group acquired mutations and underwent another round of purifying selection, which isolated those with alleles for antibiotic resistance. In addition to this experiment, the researchers used computer simulations to dissect the evolutionary mechanism and found that its key component could be the preliminary selection of hibernating bacteria—it seemed to accelerate the subsequent selection of resistant bacteria by a factor of twenty. This discovery could suggest that one way to improve antibiotics would be to target the dormant bacteria, delaying the later evolution of resistant ones.
The Hebrew University of Jerusalem. "Bacteria 'sleep', then rapidly evolve, to survive antibiotic treatments: Biophysicists use quantitative approaches from physics to understand biology." ScienceDaily. ScienceDaily, 9 February 2017. <www.sciencedaily.com/releases/2017/02/170209142558.htm>.