Beta-lactam

Beta-lactam

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-|A beta-lactam ring (β-lactam) or penam is a lactam with a heteroatomic ring structure, consisting of three carbon atoms and one nitrogen atom [Heterocyclic chemistry T.L. Gilchrist ISBN 0-582-01421-2 ] .

Clinical significance

The beta-lactam ring is part of the structure of several antibiotic families, principally the penicillins, cephalosporins, carbapenems and monobactams, which are therefore also called "beta-lactam antibiotics". These antibiotics work by inhibiting the bacterial cell wall synthesis. This has a lethal effect on bacteria, especially on Gram-positive ones. Bacteria can become resistant against beta-lactam antibiotics by expressing beta-lactamase.

History

The first synthetic β-lactam ever was prepared by Hermann Staudinger in 1907 by reaction of the Schiff base of aniline and benzaldehyde with diphenylketene ["Hugo (Ugo) Schiff, Schiff Bases, and a Century of b-Lactam Synthesis" Thomas T. Tidwell Angew. Chem. Int. Ed. 2008, 47, 1016–1020 DOI|10.1002/anie.200702965 ] [H. Staudinger, Justus Liebigs Ann. Chem. 1907, 356, 51 – 123.] in a [2+2] cycloaddition::

Beta-lactam resistance

Because of the popularity of beta-lactam drugs, certain bacteria have been able to develop counter-measures to traditional drug therapies. An enzyme called beta-lactamase is present in many different types of bacteria, which serves to 'break' the beta lactam ring, which effectively nullifies the antibiotic's effectiveness.

As a response to bacterial resistance to beta-lactam drugs, there are drugs, such as Augmentin, which are designed to disable the beta-lactamase enzyme. Augmentin is made of amoxicillin, a beta-lactam antibiotic, and clavulanic acid, a beta-lactamase inhibitor. The clavulanic acid is designed to overwhelm all beta-lactamase enzymes, bind irreversibly to them, and effectively serve as an antagonist so that the amoxicillin is not affected by the beta-lactamase enzymes.

Secondary beta-lactam drug resistance

As a response to decreased efficacy of beta-lactamase, some bacteria have changed the proteins that beta-lactam antibiotics bind, the penicillin binding proteins (PBPs). Since the PBPs no longer recognize the beta-lactams, the antibiotics are essentially useless. This is the mechanism behind the methicillin-resistant Staphylococcus aureus (MRSA).

See also

* ATC code J01#J01C Beta-lactam antibacterials.2C penicillins
* Bacteria

External links

* [http://www.organic-chemistry.org/synthesis/heterocycles/lactams/beta-lactams.shtm Synthesis of beta-lactams]

References


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Look at other dictionaries:

  • beta-lactam — Lactam Lac tam, n. [Lactone + amido.] (Chem.) One of a series of anhydrides of an amido type, analogous to the lactones, as oxindol; a cyclic amide. [1913 Webster] {beta lactam} or {[beta] lactam}, (a) a lactam in which the amide bond is… …   The Collaborative International Dictionary of English

  • beta-lactam — Lactam Lac tam, n. [Lactone + amido.] (Chem.) One of a series of anhydrides of an amido type, analogous to the lactones, as oxindol; a cyclic amide. [1913 Webster] {beta lactam} or {[beta] lactam}, (a) a lactam in which the amide bond is… …   The Collaborative International Dictionary of English

  • beta-lactam — be·ta lac·tam or ß lactam .bāt ə lak .tam, chiefly Brit .bē tə n any of a large class of natural and semisynthetic antibiotics (as the penicillins and cephalosporins) with a lactam ring ß lactam, ß lactamase var of BETA LACTAM, BETA LACTAMASE …   Medical dictionary

  • beta-lactam antibiotic — Lactam Lac tam, n. [Lactone + amido.] (Chem.) One of a series of anhydrides of an amido type, analogous to the lactones, as oxindol; a cyclic amide. [1913 Webster] {beta lactam} or {[beta] lactam}, (a) a lactam in which the amide bond is… …   The Collaborative International Dictionary of English

  • Beta-lactam Ring Records — is an American record label that began in 2000 in Austin, Texas and relocated to [Portland, Oregon] in 2001. External links* [http://www.blrrecords.com// Official site] …   Wikipedia

  • beta-lactam — beta lac·tam …   English syllables

  • Beta-lactam antibiotic — β lactam antibiotics are a broad class of antibiotics that include penicillin derivatives, cephalosporins, monobactams, carbapenems, and β lactamase inhibitors, that is, any antibiotic agent that contains a β lactam nucleus in its molecular… …   Wikipedia

  • beta-lactam antibiotic — one of a group of drugs that includes the penicillin and the cephalosporin. All have a four membered beta lactam ring as part of their molecular structure. Beta lactam antibiotics function by interfering with the growth of the cell walls of… …   Medical dictionary

  • beta-lactam antibiotic — one of a group of drugs that includes the penicillins and the cephalosporins. All have a four membered beta lactam ring as part of their molecular structure. Beta lactam antibiotics function by interfering with the growth of the cell walls of… …   The new mediacal dictionary

  • beta-lactam — noun A lactam having a four membered ring structure; a structural element of many antibiotics such as penicillin. Syn: penam …   Wiktionary

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