Extended Data Fig. 1: Schematic of the antibiotic survival landscape of the bacterial strains in this study.

a. In wildtype cells, the survival to the antibiotic is dictated by the minimum inhibitory concentration (MIC), which is the lowest concentration of an antibiotic that achieves inhibition of growth. In a population of antibiotic-sensitive cells, the landscape partition between survival and death is independent of cell density. b. Antimicrobial resistance factors (that is, native β-lactamase) decrease the susceptibility of the bacterial cell to the antibiotic, increasing the MIC. In a population of antibiotic-resistant cells, the partition between survival and death is also independent of cell density. c. Density-dependent survival effect in spTEM1-expressing strains. Secretion and extracellular assembly of the spTEM1 β-lactamase preclude self-protection in producer cells and makes the partition of the antibiotic survival landscape a function of the cell density. Below the critical cell density threshold, the engineered cells are as susceptible to the antibiotic as wildtype cells. Above the cell density threshold, the engineered cells can survive the antibiotic to the same extent as their neighboring cells, offering population-wide protection.