Mycobacterium tuberculosis (Mtb) expresses a broad-spectrum â-lactamase (BlaC) that mediates resistance to one of the highly effective antibacterials, â-lactams. Nonetheless, â-lactams showed mycobactericidal activity in combination with â-lactamase inhibitor, clavulanate (Clav). However, the mechanistic aspects of how Mtb responds to â-lactams such as Amoxicillin in combination with Clav (referred as Augmentin [AG]) are not clear. Here, we identified cytoplasmic redox potential and intracellular redox sensor, WhiB4, as key determinants of mycobacterial resistance against AG. Using computer-based, biochemical, redox-biosensor, and genetic strategies, we uncovered a functional linkage between specific determinants of â-lactam resistance (e.g. â-lactamase) and redox potential in Mtb. We also describe the role of WhiB4 in coordinating the activity of â-lactamase in a redox-dependent manner to tolerate AG. Disruption of WhiB4 enhances AG tolerance, whereas overexpression potentiates AG activity against drug-resistant Mtb. Our findings suggest that AG can be exploited to diminish drug-resistance in Mtb through redox-based interventions.
Amoxicillin-Potassium Clavulanate Combination Anti-Bacterial Agents