Bacteria are commonly known as simple, randomly moving microorganisms. However, it has recently been revealed that bacteria can remember past experiences and transmit that memory to descendants over multiple generations. This could provide clues to explain why antibiotics and vaccines do not work effectively.
Researchers at Hebrew University in Jerusalem published their findings on the hidden behavioral patterns of bacteria using new technology in the international journal "Cell" on the 27th.
The research team developed a new technology to analyze the ribonucleic acid (RNA), genetic, and cellular characteristics of small groups (microcolonies) formed by a single bacterium. This technology can differentiate whether the differences among bacteria are simply due to genetic mutations or are a result of "epigenetic memories" where the genes do not change but the expression methods differ.
Experimental results showed that pathogens like Escherichia coli and Staphylococcus aureus were divided into multiple subgroups even within a single infection. Some groups activated pathogenic genes to better attach to the human body, while others activated survival genes to endure harsh environments.
Such memories based on the environment persisted for more than 20 generations. For example, bacteria that encountered antibiotics passed that experience to their offspring, allowing the descendants to develop traits that enable them to withstand antibiotics more effectively.
However, there were limits to the bacteria's memory. Once nutrients ran out and the bacteria entered a stagnation phase where they could no longer grow, they forgot their memories and reverted to an initial state. This means bacteria adjust their strategies based on the situation.
The research team believes this discovery explains why antibiotics and vaccines often fail. Existing diagnostic methods typically analyze only one or two randomly collected bacterial samples. However, in actual infection sites, bacteria with multiple memories coexist simultaneously. Therefore, if other groups that were not detected survive, it becomes difficult for treatment to be effective.
When applying the developed technology to actual patients with urinary tract infections or bloodstream infections, it was found that bacteria resistant to antibiotics coexisted alongside those that were not resistant within the same patient.
Nathalie Q. Balaban, a professor at Hebrew University, noted, "Infections are not a mass of single bacteria, but rather an alliance of bacteria with various strategies," emphasizing that "effective treatment requires understanding and targeting all groups."
References
Cell (2025), DOI: https://doi.org/10.1016/j.cell.2025.08.001