What is the mechanism of action of penicillin antibiotics?

Penicillin antibiotics primarily function by inhibiting bacterial cell wall synthesis. This action is crucial because the integrity of the bacterial cell wall is essential for maintaining the shape and osmotic balance of the bacterium. The active component of penicillin binds to and inhibits the transpeptidase enzyme, also known as penicillin-binding proteins (PBPs), which plays a vital role in cross-linking the peptidoglycan layers during cell wall formation.

As a consequence of this inhibition, bacteria are unable to effectively form their protective cell walls, leading to cell lysis and ultimately bacterial death, particularly in actively growing bacteria. This mechanism is effective against a wide range of gram-positive bacteria and some gram-negative bacteria, which rely on robust cell wall structures for survival.

Other options, such as inhibiting protein synthesis, disrupting DNA replication, or interfering with folic acid synthesis, describe mechanisms utilized by different classes of antibiotics but are not applicable to penicillin. For example, antibiotics like tetracyclines and aminoglycosides target protein synthesis, while fluoroquinolones disrupt DNA replication. Sulfonamides are known for their interference with folic acid synthesis. Understanding the specific action of penicillin helps in selecting appropriate antibiotic treatments based on the infection