PNGM-1 is a subclass B3 metallo-beta-lactamase first identified from a deep-sea sediment meta-genome. PNGM-1 is shown to reduce susceptibility to extended- and broad-spectrum cephalosporins, carbapenems, and penicillins. PNGM-1 is a novel metallo-beta-lactamase which predates the current antibiotic era.