A 62-year-old male with a history of recurrent urinary tract infections (UTIs) is admitted with sepsis due to multi-drug resistant Escherichia coli. The infection is found to be resistant to β-lactam antibiotics. His physician explains that bacterial β-lactamase enzymes, which break down antibiotics, often rely on transition metals for their function. Which of the following transition metals is a cofactor in Type II β-lactamases, enabling bacterial resistance to β-lactam antibiotics?
