A beta-lactam (β-lactam) ring is a four-membered lactam. 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. Up to 1970, most β-lactam research was concerned with the penicillin and cephalosporin groups, but since then, a wide variety of structures have been described.
Beta-lactamases (β-lactamases) are enzymes produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems (ertapenem), although carbapenems are relatively resistant to beta-lactamase. Beta-lactamase provides antibiotic resistance by breaking the antibiotics' structure. These antibiotics all have a common element in their molecular structure: a four-atom ring known as a beta-lactam (β-lactam) ring. Through hydrolysis, the enzyme lactamase breaks the β-lactam ring open, deactivating the molecule's antibacterial properties.
β-lactam antibiotics are antibiotics that contain a beta-lactam ring in their chemical structure. This includes penicillin derivatives (penams), cephalosporins and cephamycins (cephems), monobactams, carbapenems and carbacephems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Until 2003, when measured by sales, more than half of all commercially available antibiotics in use were β-lactam compounds. The first β-lactam antibiotic discovered, penicillin, was isolated from a strain of Penicillium rubens.
In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The name of the compound is composed of a base, which includes the carbon of the −C≡N, suffixed with "nitrile", so for example CH3CH2C≡N is called "propionitrile". The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.
The cephalosporins are a class of β-lactam antibiotics originally derived from the fungus Acremonium, which was previously known as Cephalosporium.
Ceftriaxone, sold under the brand name Rocephin, is a third-generation cephalosporin antibiotic used for the treatment of a number of bacterial infections. These include middle ear infections, endocarditis, meningitis, pneumonia, bone and joint infections, intra-abdominal infections, skin infections, urinary tract infections, gonorrhea, and pelvic inflammatory disease. It is also sometimes used before surgery and following a bite wound to try to prevent infection. Ceftriaxone can be given by injection into a vein or into a muscle.
Cefacetrile is a broad-spectrum first generation cephalosporin antibiotic effective in gram-positive and gram-negative bacterial infections. It is a bacteriostatic antibiotic. Cefacetrile is marketed under the trade names Celospor, Celtol, and Cristacef, and as Vetimast for the treatment of mammary infections in lactating cows.
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Brevibacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation.
Cefapirin is an injectable, first-generation cephalosporin antibiotic. It is marketed under the trade name Cefadyl. Production for use in humans has been discontinued in the United States.
Enzyme catalysis is the increase in the rate of a process by an "enzyme", a biological molecule. Most enzymes are proteins, and most such processes are chemical reactions. Within the enzyme, generally catalysis occurs at a localized site, called the active site.
Cefquinome is a fourth-generation cephalosporin with pharmacological and antibacterial properties valuable in the treatment of coliform mastitis and other infections. It is only used in veterinary applications.
Biotransformation is the biochemical modification of one chemical compound or a mixture of chemical compounds. Biotransformations can be conducted with whole cells, their lysates, or purified enzymes. Increasingly, biotransformations are effected with purified enzymes. Major industries and life-saving technologies depend on biotransformations.
Thienamycin is one of the most potent naturally produced antibiotics known thus far, discovered in Streptomyces cattleya in 1976. Thienamycin has excellent activity against both Gram-positive and Gram-negative bacteria and is resistant to bacterial β-lactamase enzymes. Thienamycin is a zwitterion at pH 7.
Beta-lactamases are a family of enzymes involved in bacterial resistance to beta-lactam antibiotics. In bacterial resistance to beta-lactam antibiotics, the bacteria have beta-lactamase which degrade the beta-lactam rings, rendering the antibiotic ineffective. However, with beta-lactamase inhibitors, these enzymes on the bacteria are inhibited, thus allowing the antibiotic to take effect. Strategies for combating this form of resistance have included the development of new beta-lactam antibiotics that are more resistant to cleavage and the development of the class of enzyme inhibitors called beta-lactamase inhibitors. Although β-lactamase inhibitors have little antibiotic activity of their own, they prevent bacterial degradation of beta-lactam antibiotics and thus extend the range of bacteria the drugs are effective against.
Cephaloridine is a first-generation semisynthetic derivative of antibiotic cephalosporin C. It is a Beta lactam antibiotic, like penicillin. Its chemical structure contains 3 cephems, 4 carboxyl groups and three pyridinium methyl groups.
Isopenicillin N synthase (IPNS) is a non-heme iron protein belonging to the 2-oxoglutarate (2OG)-dependent dioxygenases oxidoreductase family. This enzyme catalyzes the formation of isopenicillin N from δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine (LLD-ACV).
In enzymology, a glutaryl-7-aminocephalosporanic-acid acylase (EC 3.5.1.93) is an enzyme that catalyzes the chemical reaction
Cephalosporins are a broad class of bactericidal antibiotics that include the β-lactam ring and share a structural similarity and mechanism of action with other β-lactam antibiotics. The cephalosporins have the ability to kill bacteria by inhibiting essential steps in the bacterial cell wall synthesis which in the end results in osmotic lysis and death of the bacterial cell. Cephalosporins are widely used antibiotics because of their clinical efficiency and desirable safety profile.
Neisseria gonorrhoeae, the bacterium that causes the sexually transmitted infection gonorrhea, has developed antibiotic resistance to many antibiotics. The bacteria was first identified in 1879.
Ceftolozane/tazobactam, sold under the brand name Zerbaxa, is a fixed-dose combination antibiotic medication used for the treatment of complicated urinary tract infections and complicated intra-abdominal infections in adults. Ceftolozane is a cephalosporin antibiotic, developed for the treatment of infections with gram-negative bacteria that are resistant to conventional antibiotics. It was studied for urinary tract infections, intra-abdominal infections and ventilator-associated bacterial pneumonia.
