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Because of this inhibition the antibiotics are most effective when the bacteria are in the logarithmic phase of growth, where then they are synthesizing the cell wall. If the bacteria are in the stationary phase of growth, then there is no wall synthesizing in progress, and the antibiotics have much lower effect. [3]
With advances in medicinal chemistry, most modern antibacterials are semisynthetic modifications of various natural compounds. [79] These include, for example, the beta-lactam antibiotics, which include the penicillins (produced by fungi in the genus Penicillium), the cephalosporins, and the carbapenems.
/ 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 ...
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.
Tetracyclines are generally used in the treatment of infections of the urinary tract, respiratory tract, and the intestines and are also used in the treatment of chlamydia, especially in patients allergic to β-lactams and macrolides; however, their use for these indications is less popular than it once was due to widespread development of resistance in the causative organisms.
Production of antibiotics is a naturally occurring event, that thanks to advances in science can now be replicated and improved upon in laboratory settings. Due to the discovery of penicillin by Alexander Fleming, and the efforts of Florey and Chain in 1938, large-scale, pharmaceutical production of antibiotics has been made possible.
Methicillin and other β-lactam antibiotics are structural analogs of D-alanyl-alanine, and the transpeptidase enzymes that bind to them are sometimes called penicillin-binding proteins (PBPs). [3] Methicillin is actually a penicillinase-resistant β-lactam antibiotic. Penicillinase is a bacterial enzyme produced by bacteria resistant to other ...
Piperacillin is a broad-spectrum β-lactam antibiotic of the ureidopenicillin class. [1] The chemical structure of piperacillin and other ureidopenicillins incorporates a polar side chain that enhances penetration into Gram-negative bacteria and reduces susceptibility to cleavage by Gram-negative beta lactamase enzymes.