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Since the discovery of the beta-lactam antibiotic penicillin, the rates of antimicrobial resistance have increased. [38] Over time, methods for testing the sensitivity of bacteria to antibiotics have developed and changed. [25] Alexander Fleming in the 1920s developed the first method of susceptibility testing.
β-Lactam antibiotics are indicated for the prevention and treatment of bacterial infections caused by susceptible organisms. At first, β-lactam antibiotics were mainly active only against gram-positive bacteria, yet the recent development of broad-spectrum β-lactam antibiotics active against various gram-negative organisms has increased their usefulness.
Beta-lactam ring in red. Escherichia coli bacteria on the right are sensitive to two beta-lactam antibiotics, and do not grow in the semi-circular regions surrounding antibiotics. E. coli bacteria on the left are resistant to beta-lactam antibiotics, and grow next to one antibiotic (bottom) and are less inhibited by another antibiotic (top).
The β-lactam core structures. (A) A penam.(B) A carbapenam.(C) An oxapenam.(D) A penem.(E) A carbapenem.(F) A monobactam.(G) A cephem.(H) A carbacephem.(I) An oxacephem. This is a list of common β-lactam antibiotics—both administered drugs and those not in clinical use—organized by structural class.
A lactam is a cyclic amide, and beta-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl. The simplest β-lactam possible is 2-azetidinone. β-lactams are significant structural units of medicines as manifested in many β-lactam antibiotics. [2]
/ ˌ s ɛ f ə l ə ˈ s p ɔːr ɪ n, ˌ k ɛ-,-l oʊ-/ [1] [2]) are a class of β-lactam antibiotics originally derived from the fungus Acremonium, which was previously known as Cephalosporium. [3] Together with cephamycins, they constitute a subgroup of β-lactam antibiotics called cephems. Cephalosporins were discovered in 1945, and first ...
PBPs normally catalyze the cross-linking of the bacterial cell wall, but they can be permanently inhibited by penicillin and other β-lactam antibiotics. (NAM = N-acetylmuramic acid; NAG = N-acetylglucosamine) [2] Penicillin-binding proteins (PBPs) are a group of proteins that are characterized by their affinity for and binding of penicillin.
In general, treatment with cephalosporins results in induction of AmpC beta-lactamase. [2] Treatment with an aminoglycoside or carbapenem is usually indicated. Carbapenems are a class of beta-lactam antibiotics with a broad spectrum of antibacterial activity. They have a structure that renders them highly resistant to beta-lactamases.