Antibiotic resistance breakers (ARBs) are adjunct compounds that typically have little direct antibacterial effect but work by inhibiting resistance mechanisms of bacteria.
ARBs are given with antibiotics to restore or enhance their activity against resistant bacteria. ARBs are especially useful in Gram‑negative pathogens that exhibit many evolving multidrug resistance mechanisms (MDR and XDR).
Examples of ARBs include β‑lactamase inhibitors (BLIs), which work by preventing enzymatic antibiotic degradation and restoring β‑lactam (BL) activity without much standalone effect. There are many clinically relevant and successful Gram‑negative BL/BLI combinations such as: Ceftazidime–avibactam or sulbactam–durlobactam. These combinations exemplify “resistance breaking” by restoring susceptibility where carbapenems or cephalosporins alone fail.