WIKIMEDIA, GRAHAM BEARDSPopulations of Escherichia coli grown in the lab quickly evolve tolerance when exposed to repeated treatments with the antibiotic ampicillin, according to a study published today (June 25) in Nature. Specifically, the bacteria evolved to stay in a dormant “lag” phase for just longer than three-, five-, or eight-hour-long treatment courses, before waking up and growing overnight until the next round of treatment began.
“I was very surprised that the bacteria are able to modify their lag time just as much as they need to,” said microbiologist Tom Coenye of the Laboratory of Pharmaceutical Microbiology (LPM) at Gent University in Belgium, who was not involved in the research.
The study highlights the importance of antibiotic tolerance, which allows bacteria to survive even high levels of antibiotics by remaining dormant, Coenye added. Researchers and clinicians may be quick to assume than an unsuccessful antibiotic treatment failed as a result of resistance, in which the microbe has evolved to grow in the presence of the drug, but tolerance can be just as threatening to a patient’s health. “Resistance is very well known; the issue of tolerance is much less known,” Coenye ...
