A 58-year-old man with a history of type 2 diabetes mellitus presents to the emergency department with fever, chills, and worsening confusion. He is hypotensive and tachycardic. Blood cultures are drawn, and broad-spectrum antibiotics are initiated. The next day, blood cultures grow Escherichia coli that produces extended-spectrum β-lactamases (ESBLs). Which of the following antibiotics is most appropriate for definitive therapy in this patient?