JDB-1-200, an Atypically Modified Carbapenem with Standalone In Vitro Activity against KPC-Producing Enterobacterales.

Carbapenem-resistant Enterobacterales (CRE), including Escherichia coli and Klebsiella pneumoniae are increasingly common pathogens. Resistance in CRE is often associated with production of K. pneumoniae (KPC) carbapenemases. We report a structurally modified meropenem derivative, JDB-1-200 (i.e., 8-epi-meropenem, in which the stereochemistry of the C8 hydroxyl is inverted), displaying enhanced activity relative to meropenem against KPC-producing CRE. JDB-1-200 alone displayed superior activity (MICs of 0.5 to 1 mg/L, compared with >8 mg/L for meropenem) against several clinically relevant Enterobacterales, including KPC-producing K. pneumoniae and Citrobacter freundii. Crystallographic analysis of JDB-1-200 complexes with the E166Q deacylation-deficient KPC-2 mutant, compared with an analogous meropenem (8R-hydroxyl) complex, indicates that the improvement arises from the JDB 8S-hydroxyl group acting as a hydrogen-bond donor to the hydrolytic water, slowing acyl-enzyme hydrolysis, with similar interactions observed in a CTX-M-15:JDB-1-200 complex. Kinetic inhibition data for KPC-2 and CTX-M-15 indicate that JDB-1-200 could be used alone or alongside a β-lactamase inhibitor for effective CRE treatment.