Definition:
Tolerability is a transient, reversible state in which bacteria survive exposure to an antibiotic for longer periods without an increase in minimum inhibitory concentration (MIC).
Unlike resistance, which allows growth at higher antibiotic concentrations, or persistence, where a small subpopulation remains dormant, tolerability reflects a population-wide delay in killing under otherwise lethal conditions. It often arises from physiological adaptations such as slowed metabolism, altered growth dynamics, or stress-response pathways. Increased bacterial tolerability may contribute to treatment failure by reducing the effectiveness of antibiotic killing and facilitating the subsequent evolution of resistance.
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