Microcin MccI47 selectively inhibits enteric bacteria and reduces carbapenem-resistant colonization when administered an engineered live biotherapeutic.

The gastrointestinal (GI) tract is the reservoir for multidrug resistant (MDR) pathogens, specifically carbapenem-resistant (CR) and other , which often lead to the spread of antimicrobial resistance genes, severe extraintestinal infections, and lethal outcomes. Selective GI decolonization has been proposed as a new strategy for preventing transmission to other body sites and minimizing spreading to susceptible individuals. Here, we purify the to-date uncharacterized class IIb microcin I47 (MccI47) and demonstrate potent inhibition of numerous , including multidrug-resistant clinical isolates, at concentrations resembling those of commonly prescribed antibiotics.