What is the primary mechanism of action of Cephalexin?

Cephalexin is a first-generation cephalosporin antibiotic, and its primary mechanism of action involves binding to and inhibiting penicillin-binding proteins (PBPs). PBPs are essential for bacterial cell wall synthesis, and by inhibiting these proteins, cephalexin disrupts the formation of the peptidoglycan layer, which is crucial for maintaining cell wall integrity. This disruption ultimately leads to cell lysis and death of the bacteria, making cephalexin effective against a wide variety of gram-positive bacteria and some gram-negative bacteria.

The other options reflect mechanisms of action associated with different classes of antibiotics. For instance, inhibiting bacterial DNA gyrase is characteristic of fluoroquinolones, while disrupting ribosome function is noted in antibiotics like tetracyclines and aminoglycosides. Inhibiting RNA polymerase activity pertains to rifamycins. These mechanisms differ significantly from that of cephalexin, which specifically targets the cell wall synthesis process.