Antibiotic tolerance, persistence, and resistance of the evolved minimal cell, *Mycoplasma mycoides* JCVI-Syn3B

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.