Sometimes, infections can flare up after a seemingly successful course of antibiotics, even when no resistant bacteria are involved. The phenomenon was the subject of recent research conducted by KU Leuven Centre of Microbial and Plant Genetics scientists in Belgium.
The scientists treated E. coli gut bacteria with daily antibiotic doses in a lab setting. They discovered that even though most bacteria were killed initially, some bacteria found a quick way to adapt with minimal changes in their genetic material.
The result was the rapid development of many persister cells, which are in a dormant state and are not susceptible to antibiotics. These cells are not resistant to antibiotics, so they cannot continue growing during an antibiotic treatment, but they can survive the treatment and continue reproducing afterward. They are called "tolerant" cells.
"These tolerant cells can just sit out treatment," said lead author Jan Michiels, PhD. "On the first day of treatment, they are already present, albeit in small numbers. They ensure that the population is not wiped out and that it can be reconstituted after the antibiotic treatment. Eventually, you end up with an entire population that is tolerant to several antibiotics."
According to Dr. Michiels, it's common to screen antibiotic treatments for resistance, but not for tolerance, so "figuring out how and why more bacteria develop antibiotic tolerance is important to improve future therapies and thus save lives."
More articles on antibiotics:
CDC's Vital Signs report puts antibiotic-resistant HAIs in the crosshairs
Researchers link antibiotic resistance with chemical found in soap
Subway prioritizes antibiotic stewardship with new antibiotic-free meat