Heterogeneous Flagellar Expression in Single Salmonella Cells Promotes Diversity in Antibiotic Tolerance

Abstract

Antibiotic resistance and tolerance pose a severe threat to human health. How bacterial pathogens acquire antibiotic tolerance is not clear. Here, we show that the human and animal pathogen Salmonella divides its population into subgroups that are different in their abilities to tolerate antibiotic treatments. In a Salmonella population that is genetically identical, some cells express flagella to move toward nutrients, while other cells do not express flagella. Interestingly, we show that Salmonella cells that do not express flagella are more tolerant to antibiotics. We have further determined the mechanism underlying such diverse responses to antibiotics. Flagellar motility uses cellular energy stored in the form of proton motive force and makes cells less efficient in pumping out toxic molecules such as antibiotics. The overall bacterial population therefore gains benefits from such diversity to quickly adapt to different environmental conditions.