Environmental conditions define the energetics of bacterial dormancy and its antibiotic susceptibility

Bacterial cells that stop growing but maintain viability and the capability to regrow are termed dormant and have been shown to transiently tolerate high concentrations of antimicrobials. Links between tolerance and cellular energetics as a possible explanation for the tolerance, have been investigated and have produced mixed and seemingly contradictory results. Because dormancy merely indicates growth arrest, which can be induced by various stimuli, we hypothesise that dormant cells may exist in a range of energetic states that depend on the environment. To energetically characterise different dormancies, we first induce them in a way that results in dormant populations and subsequently measured both of their main energy sources, the PMF magnitude and the concentration of ATP. We find that different types of dormancy exhibit characteristic energetic profiles that vary in level and dynamics. The energetic makeup was associated with survival to some antibiotics, but not others. Our findings portray dormancy as a state that is rich in phenotypes with various stress survival capabilities. Because environmental conditions outside of the lab often halt or limit microbial growth, a typologisation of dormant states may yield relevant insights on the survival and evolutionary strategies of these organisms. This is the supporting data for the upcoming publication Leonardo Mancini, Teuta Pilizota (pre-accepted), "Environmental conditions define the energetics of bacterial dormancy and its antibiotic susceptibility", Biophysical journal.