Clavulanic acid is produced by the fermentation of Streptomyces clavuligerus. It is a β-lactam structurally related to the penicillins and possesses the ability to inactivate a wide variety of β-lactamases by blocking the active sites of these enzymes. Clavulanic acid is particularly active against the clinically important plasmid-mediated β-lactamases frequently responsible for transferred drug resistance to penicillins and cephalosporins. Clavulanic acid is used in conjunction with amoxicillin for the treatment of bronchitis and urinary tract, skin, and soft tissue infections caused by beta-lactamase producing organisms. Clavulanic acid competitively and irreversibly inhibits a wide variety of beta-lactamases, commonly found in microorganisms resistant to penicillins and cephalosporins. Binding and irreversibly inhibiting the beta-lactamase results in a restauration of the antimicrobial activity of beta-lactam antibiotics against lactamase-secreting-resistant bacteria. By inactivating beta-lactamase (the bacterial resistance protein), the accompanying penicillin/cephalosporin drugs may be made more potent as well.

Amoxicillin is one of the widely prescribed antibacterial agents, which was discovered by scientists at Beecham Research Laboratories in 1972. In the US GlaxoSmithKline markets it under the original brand name Amoxil. It is the first line treatment for middle ear infections. It is also used for strep throat, pneumonia, skin infections, and urinary tract infections it is taken by mouth. Amoxicillin inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. This results in a formation of defective cell wall and a cell death. Common side effects include nausea and rash. It may also increase the risk of yeast infections and, when used in combination with clavulanic acid, diarrhea. It should not be used in those who are allergic to penicillin.