Amoxicillin is an extended-spectrum ß-lactam antibiotic with a structure similar to that of ampicillin. It is effective against a variety of ß-lactamase negative bacteria including E. coli and various Streptococcus and Staphylococcus bacteria. It is also effective against a variety of other gram-negative and gram-positive bacteria. Amoxicillin sodium salt is freely soluble in aqueous solution.

Penicillins are a type of β-lactam antibiotic consisting of a four-membered β-lactam ring bound to a five-membered thiazolidine ring. This two-ring system causes distortion of the β-lactam amide bond, resulting in decreased resonance stabilization and increased reactivity. β-lactams inhibit the formation of peptidoglycan cross-links within bacterial cell walls by targeting penicillin-binding proteins or PBPs. Consequently, the bacterial cell wall becomes weak and cytolysis occurs. Resistance to β-lactam antibiotics occurs in the presence of cells containing plasmid encoded extended spectrum β-lactamases or ESBLs.

Antibiotics are often used in clinical in vitro tests known as antimicrobial susceptibility tests or ASTs to determine their efficacy against certain bacterial species. They are tested against gram-negative and gram-positive bacteria using panels, discs, and MIC strips by medical microbiologists. ASTs decrease the risk of using an antibiotic against bacteria exhibiting resistance to it, and the results are used in clinical settings to determine which antibiotic(s) to prescribe for various infections.

MOLECULAR BIOLOGY GRADE