Exploiting the fitness cost of metallo-β-lactamase expression can overcome antibiotic resistance in bacterial pathogens

Abstract Carbapenem antibiotics represent the most reliable last-resort treatment for bacterial infections. The widespread acquisition of metallo-β-lactamases (MBLs), such as VIM-2, is a significant contributor to the emergence of carbapenem-resistant pathogens. The absence of clinically available MBL inhibitors necessitates the development of new approaches to treat carbapenem-resistant infections. Herein, we demonstrate that Enterobacteriaceae and Pseudomonas aeruginosa expressing VIM-2 have impaired growth in clinically relevant zinc-deprived environments, including human serum and murine infection models. Using transcriptomic, genomic, and chemical probes, we identified molecular pathways critical for VIM-2 expression in Escherichia coli under zinc limitation. Of particular note were envelope stress response pathways. Disruption of envelope stress response pathways significantly reduced the growth of VIM-2-expressing bacteria in vitro and in vivo. Furthermore, we demonstrated that VIM-2 expression disrupts the integrity of the outer membrane, rendering VIM-2-expressing bacteria more susceptible to antibiotics that are typically ineffective against Gram-negative bacteria, such as azithromycin. Accordingly, using a systemic murine infection model, we revealed that azithromycin has therapeutic potential in treating VIM-2-expressing Klebsiella pneumoniae. In all, our findings provide a framework to uncover and exploit the fitness trade-offs of resistance, potentially accelerating the discovery of novel treatments for multi-drug resistant bacteria.