How do beta-lactamase inhibitors augment penicillin therapy?

• A. They inhibit bacterial beta-lactamases, protecting the penicillin from degradation and extending its spectrum
• B. They kill bacteria directly
• C. They inactivate penicillin
• D. They reduce absorption of penicillin

Answer: (A)

Beta-lactamase inhibitors protect penicillins from enzymatic destruction by bacteria. Some bacteria produce beta-lactamase enzymes that hydrolyze the beta-lactam ring of penicillins, inactivating the drug. These inhibitors resemble beta-lactam antibiotics enough to bind the enzyme and inactivate it (often by mechanism-based or covalent binding), so the penicillin can stay intact and reach its target sites to inhibit cell wall synthesis. Because the enzyme is blocked, the drug remains active against beta-lactamase–producing organisms and the combination expands the penicillin’s spectrum. On their own, these inhibitors have little antibacterial effect; their main role is to augment penicillin therapy, not to kill bacteria directly. They do not reduce penicillin absorption or inactivate it.