Beta-lactamase contributes to resistance by doing what?

• A. Degrading beta-lactam antibiotics
• B. Increasing antibiotic uptake
• C. Inhibiting bacterial replication
• D. Stabilizing cell walls

Answer: (A)

Beta-lactamase confers resistance by inactivating beta-lactam antibiotics through hydrolysis of the beta-lactam ring. That ring is essential for the drug’s ability to mimic the normal substrate of penicillin-binding proteins, so when the ring is opened, the antibiotic can no longer bind PBPs and block cell-wall synthesis. As a result, bacterial cell walls are made normally and the bacteria survive.

This enzymatic degradation is why these drugs lose effectiveness against beta-lactamase–producing strains. It also explains the use of beta-lactamase inhibitors (like clavulanate) in combination therapies, which help protect the antibiotic from the enzyme and restore activity.