Gut bacteria generate prodrugs in situ increasing systemic drug exposure

The human gut microbiome has been increasingly recognized as a metabolic compartment that influences health and therapeutic responses. While recent studies have cataloged diverse sets of drug biotransformation reactions as a result of microbial metabolism1-3, the pharmacological relevance of the resulting drug metabolites remains mostly uncharacterized. We investigated whether certain microbial drug metabolites can act as functional prodrugs. By systematically mining 871 putative drug metabolites produced by gut bacteria1, we identified microbial drug metabolites with key physicochemical properties of prodrugs. Using bacterial culturing, a genetic gain-of-function screen coupled to mass spectrometry and comparative genomics, we uncover that Bacteroidota bacteria encode conserved methyltransferases that can generate prodrugs through carboxyl methylation. As a case in point, we demonstrate that bezafibrate gets converted to a prodrug by a distinct bacterial enzyme, increasing epithelial drug permeability in vitro and systemic drug exposure in vivo in a gnotobiotic mouse model. Additionally, we tested 170 structurally and clinically diverse drugs, and demonstrate that microbial drug-prodrug conversion is a common result of gut bacterial drug biotransformation. Altogether, our findings suggest a novel mechanism of how the gut microbiota influences an individuals pharmacokinetics, and may generally cause interpersonal differences in microbiota-host metabolic interactions.