Abstract

Resistance to beta-lactam antibiotics, including the "last-resort" carbapenems, has emerged as a major threat to global health. A major resistance mechanism employed by pathogens involves the use of metallo-beta-lactamases (MBLs), zinc-dependent enzymes that inactivate most of the beta-lactam antibiotics used to treat infections. Variants of MBLs are frequently discovered in clinical environments. However, an increasing number of such enzymes have been identified in microorganisms that are less impacted by human activities. Here, an MBL from Lysobacter antibioticus, isolated from the rhizosphere, has been shown to be highly active toward numerous beta-lactam antibiotics. Its activity is higher than that of some of the most effective MBLs linked to hospital-acquired antibiotic resistance and thus poses an interesting system to investigate evolutionary pressures that drive the emergence of such biocatalysts.