KPC-2-IN-1, boronic acid derivative, is a potent KPC-2 inhibitor with K i of 0.032 μM. KPC-2-IN-1 enhances the activity of cefotaxime in KPC-2 expressing E. coli. KPC-2-IN-1 exhibits well tolerated in human HEK-293 cells, which can be used for the study of E. coli resistance to β-lactam antibiotics.