aminopenicilines

Aminopenicillins are a class of beta-lactam antibiotics derived from penicillin. They are characterized by the addition of an amino group to the penicillin nucleus, which enhances their spectrum of activity compared to earlier penicillins. This structural modification allows them to penetrate the outer membrane of certain Gram-negative bacteria more effectively.

The primary members of this class include ampicillin and amoxicillin. Both drugs are broad-spectrum antibiotics, meaning they are effective against a wider range of bacteria than penicillin G. They are commonly used to treat infections caused by susceptible Gram-positive bacteria, as well as some Gram-negative bacteria such as Haemophilus influenzae, Escherichia coli, and Proteus mirabilis.

Aminopenicillins work by inhibiting bacterial cell wall synthesis. They bind to and inactivate penicillin-binding proteins (PBPs), which are enzymes essential for the cross-linking of peptidoglycan, a major component of the bacterial cell wall. This disruption leads to a weakened cell wall and ultimately bacterial lysis.

While generally well-tolerated, aminopenicillins can cause side effects such as rash, gastrointestinal disturbances, and allergic reactions, including anaphylaxis. Resistance to aminopenicillins can develop through several mechanisms, most notably the production of beta-lactamase enzymes by bacteria, which hydrolyze the beta-lactam ring of the antibiotic, rendering it inactive. To combat this, aminopenicillins are often combined with beta-lactamase inhibitors like clavulanic acid.