beta-lactam

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Penicillin nucleus. Beta lactam is the square at the center.
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. 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.

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.

Response to beta-lactam resistance

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

Beta (uppercase Β, lowercase β and internal ϐ) is the second letter of the Greek alphabet. In the system of Greek numerals it has a value of 2. It was derived from the Phoenician letter Beth .
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lactam (the noun is a portmanteau of the words lactone + amide) is a cyclic amide. Prefixes may indicate the ring size: β-lactam (4-membered), γ-lactam (5-membered), δ-lactam (6-membered ring).
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In the nomenclature of organic chemistry, a heteroatom (from Ancient Greek heteros, different, + atomos) is any atom that is not carbon or hydrogen. It is typically, but not exclusively, nitrogen, oxygen, sulfur, phosphorus, boron, chlorine, bromine, or iodine.
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Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring. They may be either simple aromatic rings or non-aromatic rings.
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4, 2
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1

Atomic radius 70 pm
Atomic radius (calc.
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3, 5, 4, 2
(strongly acidic oxide)
Electronegativity 3.04 (Pauling scale)
Ionization energies
(more) 1st: 1402.3 kJmol−1
2nd: 2856 kJmol−1
3rd: 4578.1 kJmol−1

Atomic radius 65 pm
Atomic radius (calc.
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atom (Greek ἄτομος or átomos meaning "indivisible") is the smallest particle still characterizing a chemical element.
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antibiotic is a chemotherapeutic agent that inhibits or abolishes the growth of micro-organisms, such as bacteria, fungi, or protozoans. The term originally referred to any agent with biological activity against living organisms; however, "antibiotic" now is used to refer to
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Penicillin (sometimes abbreviated PCN) is a group of beta-lactam antibiotics used in the treatment of bacterial infections caused by susceptible, usually Gram-positive, organisms.
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The cephalosporins (IPA: [ˌkɛfəloˈspɔrən, ˌsɛfə-]) are a class of β-lactam antibiotics. Together with cephamycins they belong to a sub-group called cephems.
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Carbapenems are a class of beta-lactam antibiotics with a broad spectrum of antibacterial activity, and have a structure which renders them highly resistant to beta-lactamases.
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Monobactams are beta-lactam antibiotics wherein the beta-lactam ring is alone, and not fused to another ring (in contrast to most other beta-lactams, which have at least two rings). The only commercially available monobactam is aztreonam.
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β-lactam antibiotics are a broad class of antibiotics which include penicillin derivatives, cephalosporins, monobactams, carbapenems and β-lactamase inhibitors; basically any antibiotic agent which contains a β-lactam nucleus in its molecular structure.
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cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, which provides the cell with structural support, protection, and acts as a filtering mechanism. The cell wall also prevents over-expansion when water enters the cell.
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Bacteria

Phyla

Actinobacteria
Aquificae
Chlamydiae
Bacteroidetes/Chlorobi
Chloroflexi
Chrysiogenetes
Cyanobacteria
Deferribacteres
Deinococcus-Thermus
Dictyoglomi
Fibrobacteres/Acidobacteria
Firmicutes
Fusobacteria
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Gram-positive bacteria are those that retain a crystal violet dye during the Gram stain process.[1] Gram-positive bacteria appear blue or violet under a microscope, while Gram-negative bacteria appear red or pink.
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Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. It is a specific type of drug resistance. Antibiotic resistance evolves naturally via natural selection through random mutation, but it could also be engineered.
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Beta-lactamase is an enzyme (EC 3.5.2.6 ) produced by some bacteria that is responsible for their resistance to beta-lactam antibiotics like penicillins, cephalosporins, cephamycins and carbapenems.
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Beta-lactamase is an enzyme (EC 3.5.2.6 ) produced by some bacteria that is responsible for their resistance to beta-lactam antibiotics like penicillins, cephalosporins, cephamycins and carbapenems.
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Co-amoxiclav is the British Approved Name, in the British Pharmacopoeia, for the combination antibiotic containing Amoxicillin (as either trihydate or the sodium salt) and Clavulanic acid (as Potassium clavulanate).
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Co-amoxiclav is the British Approved Name, in the British Pharmacopoeia, for the combination antibiotic containing Amoxicillin (as either trihydate or the sodium salt) and Clavulanic acid (as Potassium clavulanate).
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Amoxicillin (INN) or amoxycillin (former BAN) is a moderate-spectrum β-lactam antibiotic used to treat bacterial infections caused by susceptible microorganisms.
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Clavulanic acid (rINN) (IPA: [klævjuˌlænɪk ˈæsəd]) is a beta-lactamase inhibitor (GlaxoSmithKline formerly Beecham) sometimes combined with penicillin group antibiotics to overcome certain types of antibiotic
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In literature, the antagonist is that against which the main character or protagonist contends. [1] An antagonist is often a Villain, but may be a force of nature, set of circumstances, an animal, or other force that is in conflict with the protaganist.
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Penicillin binding proteins (PBPs) are a group of proteins which are characterized by their affinity for and binding of penicillin. They do not just bind penicillin but all beta-lactam antibiotics which are a family of antibiotics sharing a four membered lactam ring (beta-lactam
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Bacteria

Phyla

Actinobacteria
Aquificae
Chlamydiae
Bacteroidetes/Chlorobi
Chloroflexi
Chrysiogenetes
Cyanobacteria
Deferribacteres
Deinococcus-Thermus
Dictyoglomi
Fibrobacteres/Acidobacteria
Firmicutes
Fusobacteria
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