Researchers at Baylor College of Medicine and colleagues from collaborating institutions have discovered that bacterial populations work as a team to survive antibiotics. Credit: Baylor
“Every man for himself” is not a strategy bacteria believe in, according to a new study.
Researchers at Baylor College of Medicine found evidence that bacteria pool their resources, helping quiescent or dormant cells survive, when under attack from antibiotics. The findings help explain why some bacteria are hard to eliminate and suggest potential future approaches to improve antibiotic effectiveness.
While we have long known that bacteria can help each other resist antibiotics by sharing genes, the current study investigated whether bacteria could also directly share proteins—the molecular machines that do most of the work in cells.
For the study, published in Science, researchers designed a sensitive system using the bacterium E.coli.
“We engineered one group of bacteria (donors) to make a special enzyme called Cre, and another group of the same bacteria (recipients) to contain a genetic ‘switch’ that could only flip if Cre protein entered the recipient,” said first author Alice Wen, a scholar in the Medical Scientist Training Program.
The system revealed that when donor and recipient bacteria were grown together, protein transfer occurred but was rare under normal conditions. But when the bacteria were exposed to low, non-lethal levels of antibiotics, protein transfer increased by thousands of times.
“We then investigated how proteins were moving from one cell to another,” Wen said. “We found that the transfer still occurred when donor cells were removed, leaving behind only the liquid in which they had grown. This ruled out direct cell-to-cell contact and pointed to something released into the environment.”
By combining biochemical techniques and advanced microscopy, the team discovered that tiny structures called membrane vesicles transported the proteins. Looking closer, the recipient cells showed strong signs of dormancy—these cells slowed down protein production, reduced their metabolism and activated genes associated with persistence, such as HipA.
Protein transfer also helped dormant bacteria survive exposure to lethal antibiotic doses after vesicle transfer. The results suggest that transferred proteins help dormant cells endure stress while their own protein production was shut down.
The researchers are now interested in identifying the proteins in vesicles that contribute to recipient persistence.
Data from Baylor College of Medicine