Summary Antibiotic resistance is a growing problem, but bacteria can evade antibiotic treatment via tolerance and persistence. Antibiotic persisters are a small subpopulation of bacteria that tolerate antibiotics due to a physiologically dormant state. Hence, persistence is considered a major contributor to the evolution of antibiotic-resistant and relapsing infections. Here, we used the synthetically developed minimal cell Mycoplasma mycoides JCVI-Syn3B to examine essential mechanisms of antibiotic survival. The minimal cell contains only 473 genes, and most genes are essential. Its reduced complexity helps to reveal hidden phenomenon and fundamental biological principles can be explored because of less redundancy and feedback between systems compared to natural cells. We found that Syn3B evolves antibiotic resistance to different types of antibiotics expeditiously. The minimal cell also tolerates and persists against multiple antibiotics. It contains a few already identified persister-related genes, although lacking many systems previously linked to persistence (e.g. toxin-antitoxin systems, ribosome hibernation genes).

Antibiotic persisters are a small subpopulation of bacteria that tolerate antibiotics due to a physiologically dormant state. As a result, this phenomenon (persistence) is considered a major contributor to the evolution of antibiotic-resistant and relapsing infections. However, the precise molecular mechanisms of persistence are still unclear. To examine the key mechanisms of persistence, we used the synthetically developed minimal cell Mycoplasma mycoides JCVI-Syn3B; the genome contains <500 genes, which are mostly essential. We found that Syn3B evolves expeditiously and rapidly evolves antibiotic resistance to kasugamycin. The minimum cell also tolerates and persists against multiple antibiotics despite lacking many systems related to bacterial persistence (e.g. toxin-antitoxin systems). These results show that this minimal system is a suitable system to unravel the central regulatory mechanisms of persistence.