Bacterial Resistance to Penicillins

What is the primary mechanism by which bacteria develop resistance to penicillins?

What is the primary function of β-lactamases?

What is the significance of the discovery of cephalosporin C?

What is the basis of the structure of β-lactam antibiotics?

What is the purpose of the development of new β-lactam antibiotics?

What is the effect of a single amino acid mutation on the TEM-1 β-lactamase?

What is the primary reason why the β-lactam nucleus is essential for the biological activity of penicillins?

What is the result of the cleavage of the β-lactam amide bond by a target enzyme?

What is the main reason why semi-synthetic β-lactams have been developed over the past decades?

What is the class of antibiotics to which penicillins belong?

What is the mechanism by which β-lactam antibiotics function?

Who is credited with the discovery of the first antibiotic, penicillin?

β-Lactamases and Resistance to Penicillins

Bacterial β-lactamases or penicillinase enzymes can hydrolyze the β-lactam ring, making penicillins ineffective.
There are four classes of β-lactamases, which can recognize and hydrolyze various β-lactam molecules.
TEM-1, a β-lactamase, recognizes mainly penicillins, but a single amino acid mutation can cause it to prefer cephalosporins.
New β-lactamases have been discovered that can hydrolyze directly-modified β-lactams.

Discovery of β-Lactam Antibiotics

Cephalosporin C, discovered in the 1950s, is a potent inhibitor of the enzyme in penicillin-resistant Staphylococcus aureus.
Penicillin G, or benzylpenicillin, was isolated by Florey and Chain, leading to the development of new β-lactams.
β-Lactam antibiotics are based on a bicyclic ring called β-lactam, which comprises the core chemical structure of penicillins.
The β-lactam nucleus is essential for biological activity, forming a single reactive center of the molecule.

Importance of β-Lactam Antibiotics

The discovery of penicillin by Alexander Fleming in 1928 led to extensive chemical modification of its natural structure, resulting in semi-synthetic β-lactams.
β-Lactam antibiotics are a class of natural and synthetic antibiotics with potent antimicrobial activity due to their structural similarities to the D-alanyl-D-alanine terminus of the peptidoglycan stem pentapeptide.
β-Lactam antibiotics function by inhibiting the function of penicillin-binding proteins, which catalyze the formation of peptidoglycan crosslinks.

This quiz covers the mechanism of bacterial resistance to penicillins, including the development of beta-lactamases and their classification. Learn about the different classes of beta-lactamases and their target molecules.