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Penicillinase was the first β-lactamase to be identified. It was first isolated by Abraham and Chain in 1940 from E. coli (which are gram-negative) even before penicillin entered clinical use, [ 5 ] but penicillinase production quickly spread to bacteria that previously did not produce it or produced it only rarely.
Penicillin resistance in Staphylococcus aureus [3] appeared very soon after penicillin entered general clinical use in 1943, and the mechanism of resistance was the production of β-lactamase. Modification of the penicillin molecule so that it was resistant to being broken down by β-lactamase was able to temporarily overcome this problem.
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.
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.
Some sources identify them with antipseudomonal penicillins, [2] others consider these types to be distinct. [3] This group includes the carboxypenicillins and the ureidopenicillins . Aminopenicillins , in contrast, do not have activity against Pseudomonas species, as their positively charged amino group does not hinder degradation by ...
Penicillin core structure. The β-lactam ring is part of the core structure of several antibiotic families, the principal ones being the penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called β-lactam antibiotics. Nearly all of these antibiotics work by inhibiting bacterial cell wall biosynthesis.
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.
The main classes of β-lactam antibiotics used to treat gram-negative bacterial infections include (in approximate order of intrinsic resistance to cleavage by β-lactamases) penicillins (especially aminopenicillins and ureidopenicillins), 3rd generation cephalosporins, and carbapenems.