Biological Sciences
Neomycin
Neomycin is an antibiotic medication that belongs to the aminoglycoside class. It is commonly used to treat bacterial infections, particularly in the skin and intestines. Neomycin works by inhibiting protein synthesis in bacteria, ultimately leading to their destruction. Due to its potential for causing side effects and allergic reactions, neomycin is often used cautiously and under medical supervision.
Written by Perlego with AI-assistance
Related key terms
1 of 5
11 Key excerpts on "Neomycin"
eBook - PDFBioinformatics In Agriculture
Tools And Applications
- M.Balakrishnan: Ed.(Author)
- 2021(Publication Date)
- NEW INDIA PUBLISHING AGENCY (NIPA)(Publisher)
It can also be given orally, where it is usually combined with other antibiotics. Neomycin is not absorbed from the gastrointestinal tract, and has been used as a preventive measure for hepatic encephalopathy and hypercholesterolemia. By killing bacteria in the intestinal tract, it keeps ammonia levels low and prevents hepatic encephalopathy, especially prior to GI surgery. Fig: Kanamycin 152 Bioinformatics in Agriculture: Tools and Applications Gene Details Topology Linear Length (bp) 8,545,929 G+C Content (%) 72.2 Protein-Coding Gene 7,138 rrn Operon (16S-23S-5S) 6 tRNA Gene 66 GENOMIC INFORMATION Sequence analysis of Streptomyces fradiae NCIMB 8233 has identified 21 putative open reading frames (ORFs) in the Neomycin gene cluster ( neo ) with significant protein sequence similarity to gene products involved in the biosynthesis of other DOS-containing aminoglycosides, namely butirosin ( btr ), gentamycin ( gnt ), tobramycin ( tbm ) and kanamycin ( kan ). Located at the 5-end of the neo gene cluster is the previously-characterised Neomycin phosphotransferase gene ( apH ). Three genes unique to the neo and btr clusters have been revealed by comparison of the neo cluster to btr , gnt , tbm and kan clusters. This suggests that these three genes may be involved in the transfer of a ribose moiety to the DOS ring during the antibiotic biosynthesis.( Fanglu Huang et al., 1995). Fig: Neomycin Bioinformatics of Natural Antibiotics 153 PENCILIN Penicillin (sometimes abbreviated PCN or pen) is a group of antibiotics derived from Penicilliumspecies by Alexander Fleming,1928.Penicillin antibiotics are historically significant because they are the first drugs that were effective against many previously serious diseases such as syphilis and Staphylococcus infections. Penicillins are still widely used today, though many types of bacteria are now resistant.
- Charles H. Nightingale, Paul G. Ambrose, George L. Drusano, Takeo Murakawa, Charles H. Nightingale, Paul G. Ambrose, George L. Drusano, Takeo Murakawa(Authors)
- 2007(Publication Date)
- CRC Press(Publisher)
HISTORY AND MECHANISM OF ACTION OF AMINOGLYCOSIDES The aminoglycosides include an important group of natural and semisynthetic compounds. The first parenterally administered aminoglycoside, streptomycin, was introduced in 1944 and was followed by a number of other naturally occurring compounds, which include Neomycin, kanamycin, tobramycin, gentami-cin, sisomicin, and paromomycin. Amikacin and netilmicin are semisynthetic derivatives of kanamycin and sisomicin, respectively, while isepamicin is a semisynthetic derivative of gentamicin. Arbekacin, known as habekacin, is also a semisynthetic derivative obtained by acylation of dibekacin in a reaction analo-gous to that used to produce amikacin (1,2). Like many antibiotics (i.e., macrolides, tetracyclines, and streptogramins), the bactericidal activity of the aminoglycosides is thought to be ribosomally mediated. Existing data suggest that their antibacterial activity results from inhibition of protein biosynthesis by irreversible binding of the aminoglycoside to the bacterial ribosome. The intact bacterial ribosome is a 70S particle that consists of two subunits (50S and 30S) that are assembled from three species of rRNA (5S, 16S, 147 and 23S) and from 52 ribosomal proteins. The smaller 30S ribosomal submit, which contains the 16S rRNA, has been identified as a primary target for aminoglycoside, which ultimately induces mistranslation on prokaryotic ribosomes (3,4). In order to reach their cytoplasmic ribosomal target, aminoglycosides must initially cross the outer membrane (in gram-negative organisms) and the cytoplas-mic membrane (in gram-negative and gram-positive bacteria). In gram-negative bacteria, the initial step involves ionic binding of the highly positively charged aminoglycosides to negatively charged phosphates mainly in lipopolysaccharides on the outer membrane surface, while uptake across this membrane is likely due to a “ self-promoted uptake ” mechanism (5,6).
eBook - ePub- Jim E. Riviere, Mark G. Papich, Jim E. Riviere, Mark G. Papich(Authors)
- 2017(Publication Date)
- Wiley-Blackwell(Publisher)
35 Aminoglycoside Antibiotics Mark G. Papich and Jim E. RiviereAminoglycoside antibiotics have been used in veterinary and human medicine for many years and have retained their importance for treating serious and routine infections. They are particularly valuable for treating infections caused by gram-negative bacilli, including bacteria that may be resistant to other agents. Their therapeutic importance derives from the rapid bactericidal effects, pharmacokinetics derived from a large variety of animal species, and relatively low rate of resistance. These advantages must be weighed against their potentially toxicity, requirement for administration by injection for systemic use, and high potential to produce chemical residues in food-producing animals.Pharmacology of Aminoglycosides
General Properties
Aminoglycosides include the familiar drugs gentamicin, amikacin, kanamycin, and tobramycin. They also include less familiar drugs such as Neomycin, dihydrostreptomycin, and paromomycin. Spectinomycin has been included with aminoglycosides in some textbooks, but we have instead included it with the miscellaneous antibiotics in Chapter 36. Aminoglycosides are a class of antimicrobial compounds produced from strains of Streptomyces spp. or Micromonospora spp. fungi. Those produced from Streptomyces are spelled with “mycin” and those produced from Micromonospora are spelled with “micin”. Chemically, they are aminocyclitols: hydroxyl and amino or guanidine substituted cyclohexane with amino sugars joined by glycosidic linkages to one or more of the hydroxyl groups. These molecules have excellent solubility in water but poor lipid solubility, and are thermodynamically stable over a wide range of pH values and temperatures (Lancini and Parenti, 1982; Leitner and Price, 1982; Nagabhusban et al., 1982; Pechere and Dugal, 1979). They are large molecules with molecular weights ranging from 450 to 585. The aminoglycosides are basic polycations with pKa
eBook - PDF- Ali Demir Sezer(Author)
- 2016(Publication Date)
- IntechOpen(Publisher)
Aminoglycosides induce the pleiotropism phenomenon (i.e., simultaneous changes in the expression of many genes) and also produce mRNA reading errors. Aminoglycosides are rapidly acting antibiotics with broad spectrum of action being active against strict and facultative Gram-positive and negative aerobic bacteria. Aminoglycosides could slowly accumulate through endocytosis in the lysosomes of the eukaryotic cells to an apparent cellular-to-extracellular ratio of 2 to 4, excepting some tissues like kidney proximal tubular cells, exhibiting binding sites such as megalin and acidic phospholipids where the accumulation is faster [40–43]. Spectinomycin is an aminocyclitol antibiotic related to the aminoglycosides, manifesting bacteriostatic action, usually used for the treatment of gonorrhea produced by penicillin-resistant Neisseria gonorrhoeae strains. The encapsulation of aminoglycosides in liposomes could increase the therapeutic index of the drug by reducing the level of drug delivered at the sites where the antibiotic is toxic to the therapeutic amounts necessary for the treatment of infection. This procedure also increases the aminoglycosides efficiency against intracellular bacteria. Smart Drug Delivery System 316 Tetracyclines represent a family of antibiotics inhibitory for the protein synthesis through a mechanism of blocking the attachment of aminoacyl–tRNA complex to the ribosome acceptor site (site A) [44]. These antibiotics have a broad spectrum bacteriostatic effect, being active against Gram-positive Gram-negative bacteria and protozoa, but they also kill normal gut microbiota and produce gastrointestinal disorders. Tetracyclines have the ability to accumulate in eukaryotic cells, including neutrophils [45]. Tetracyclines are strong chelating agents, their pharmacological properties being influenced by the presence of metal ions. Each of the rings of the tetracycline core can contain only linear carbon atoms in order to keep the antibiotic activity.
eBook - ePub- A. Uma, A. Angela Mercy, K. Karal Marx(Authors)
- 2020(Publication Date)
- CRC Press(Publisher)
Aminoglycosides (Aminocylitols) are a group of natural and semi-synthetic antibiotics having aminosugars linked to an aminocyclitol ring by glycosidic bond. They are mostly bactericidal drugs that share many chemical and pharmacological properties and have similar antibacterial spectrum and toxic effects. Important members of the group include Streptomycin, Neomycin, Kanamycin, Gentamicin, Amikacin, and Tobramycin.History
Streptomycin was the first member of aminoglycoside antibiotics discovered in 1944 by Waksman and co-workers from a strain of Streptomyces griseus. Neomycin was next to be isolated in 1949 followed by Kanamycin is 1957 and Gentamicin in 1963. Amikacin was the first semi-synthetic aminoglycoside obtained by chemical modification of Kanamycin. Now aminoglycosides have many members, some of which are extensively used in veterinary medicine.Chemistry and source
The aminoglycosides consist of two or more amino sugars joined in glycosidic linkages to a hexose (aminocyclitol) nucleus. In streptomycin, the hexose molecule is 2-deoxystreptamine. The presence of amino group in the structure imparts basic nature to aminoglycosides and the hydroxyl group on the sugars provides high water solubility (or poor lipid solubility) to the drugs. If these hydroxyl groups are removed (e.g., tobramycin), the drug becomes more active. Because the groups can be substituted at more than one position on the molecule, several forms of same aminoglycoside may be obtained. For examples, Neomycin is a mixture of Neomycin B, C, and fradiomycin and gentamicin is a complex of gentamicins C1, C1a, and C2. Minor differences in the chemical structures of these drugs may lead to differences in efficacy and toxicity.All aminoglycosides are produced by the soil actinomycetes. While most aminoglycosides are obtained by natural fermentation of various species of Streptomyces, some members of the group (e.g., gentamicin) are prepared from the actinomycete Micromonospora purpurea
eBook - PDF- Jesus Jimenez-Barbero, F. Javier Canada, Sonsoles Martin-Santamaria(Authors)
- 2015(Publication Date)
- Royal Society of Chemistry(Publisher)
Chang and co-workers synthesized 5 00 -modified Neomycin derivatives via click chemistry or amide linkage formation and assayed the synthetic candidates against E. coli and S. aureus strains. 35 Carboxybenzyl-protected Neomycin B ( 2 ) was regioselectively substituted with azide functionality at C-5 00 (Scheme 11.3). In the first strategy, the Neomycin B azide underwent 1,3-dipolar cyclization with various alkynes to furnish ‘‘click’’ Neomycin B analogues. In the second strategy, the azide was reduced to an amine, which was subsequently coupled with carboxylic acids or amino acids. Catalytic hydrogenation of both the analogues furnished the desired 5 00 -modified Neomycin B derivatives (Scheme 11.3). Click-based Neomycin B derivatives ( 7e and 7g ) displayed modest antimicrobial activities, on a par with parent Neomycin B. However, analogues with amide linkages manifested less antimicrobial activity than the parent aminoglycoside except the derivatives that bear long linear alkyl chain scaffolds ( 8b and 8c ) (Table 11.3). The same group has also shown that structural modifications over aminoglycosides do influence their mode of action, which in turn would govern the anti-microbial activity on the resistant bacterial strains. Binding affinity studies disclosed that unmodified pyranmycin 36 exhibits antimicrobial activity comparable to that of traditional Neomycin and exerts a similar mode of action by binding toward rRNA. The modified Neomycin 8c , armed with an amphiphilic-rich hexadecanoyl group, exerts prominent antimicrobial activity against MRSA and vancomycin-resistant enterococci (VRE) strains, which usually stymies the entry of traditional aminoglycosides. 35,37 Fluorescence-based studies demonstrated that compound 8c targets the bac-terial cell membrane, leading to enhanced permeability and cellular uptake.
eBook - PDF- Bhupendra Pushkar(Author)
- 2020(Publication Date)
- Delve Publishing(Publisher)
Indications for use: Community-developed pneumonia-mycoplasma, legionella, chlamydia infections; pertussis, campylobacter gastroenteritis and MAI. The usage of such drugs is meant for an investigative purpose in the form of anti-inflammatory agents in cystic fibrosis and for preventing atherosclerotic cardiovascular disease. 7.3.2. Aminoglycosides The aminoglycosides would be regarded as bactericidal agents used for treating severe infections. Due to apprehensions related to the development Protein Synthesis: Methods and Protocols 188 of resistance. Additionally, they possess a very limited therapeutic to a toxic ratio (i.e., the serum level is required to be powerful being a therapeutic agent would be near to the level where the toxicity of the drug would be met). Chemical Structure: Comprises of minimum two amino sugars connected through glycosidic bonds to an aminocyclitol ring. Mechanism of Action: A fast bactericidal agent in association with numerous mechanisms of action. The 30S ribosome would be considered as the primary target that would initiate the termination of premature chain and misreading of the RNA codon. Additionally, it would result in the leakage of the outer membrane of Gram-negatives. The grounds for bactericidal activity have not been comprehended entirely. Mechanism of Resistance: Enzymes being modified by aminoglycosides would be the primary channel of resistance. Adenyl transferases or phosphotransferases enzymes would help in modifying the aminoglycoside making them ineffective. In such enzymes, the genes are usually plasmid borne and it would result in them getting easily transferred among various bacterial species. Reduced absorption of the aminoglycoside through mutations in the electrochemical gradient would be an added resistance mechanism. Antibacterial spectrum: Aminoglycosides would have a rather restricted spectrum of activity.
eBook - PDFOtolaryngology
Basic Science and Clinical Review
- Thomas R. Van De Water, Hinrich Staecker(Authors)
- 2011(Publication Date)
- Thieme(Publisher)
Aminoglycosides can be divided into chemical classes. In the first class, the aminocyclitol ring is streptidine. Streptomycin, which was the first aminoglycoside used, is the only member of this class. In the second chemical class, to which all the other aminoglycosides belong, the aminocyclitol ring is 2-deoxystreptamine. Within this second class are three families: • Neomycin family • Neomycin: used orally for the treatment of hepatic encephalopathy (by killing bacteria that produce ammonium that is absorbed into the bloodstream) or topically on wounds • Kanamycin family (one of the amino sugars is glucosamine) • Kanamycin: usually used orally to decontaminate the gastrointestinal tract prior to surgery • Tobramycin: slightly broader spectrum than gentamicin; used systemically • Amikacin: broadest spectrum of all aminoglycosides • Gentamicin family (one of the amino sugars is garosamine) • Gentamicin: least broad spectrum of the aminoglycosides that are still commonly used, but still very active against many aerobic Gram-negative bacilli Due to rapid, tight, and reversible binding to sites on the 30S subunit of the bacteria (for streptomycin) or both the 50S and 30S subunits (for the other aminogly-cosides), aminoglycosides kill bacteria by inhibiting their protein synthesis and causing errors to be made in reading messenger ribonucleic acid (mRNA) codons. The binding appears to be in the region of the interface between the two ribosomal subunits. Aminoglycosides must have at least one more site or mechanism of action, because they are bactericidal, in contrast to other antibiotics that inhibit protein synthesis, which are usually bacteriostatic. However, this addi-tional site or mechanism has not been identified, and the exact nature of their interaction with bacteria remains incompletely understood.
- Clive P. Page, Ruma Anand, Stephen DeWilde(Authors)
- 2021(Publication Date)
- Elsevier(Publisher)
Spectinomycin has only one use, namely the treatment of gonorrhoeal infection due to organisms that have become resistant to penicillin. Adverse effects include rashes and vomiting.Neomycin
Neomycin is an antibiotic that is bactericidal against a wide range of Gram-positive and Gram-negative organisms, and against Mycobacterium tuberculosis. It is very poorly absorbed from the intestinal tract and because of toxicity is not given systemically. It is chiefly used to sterilize the gut before surgery. It can also be applied locally as ear or eye drops.Extensive local application to areas such as burns should be avoided, as enough absorption can occur to cause ototoxicity.Streptomycin
Streptomycin is derived from one of the Actinomyces group of fungi.Therapeutic Use
Streptomycin is usually given by intramuscular injection. The maximum concentration in the blood is reached after about 1–2 h and excretion is not completed for 24 h or more. Streptomycin is excreted in the urine. It is not absorbed after oral administration, so this route is not used except for treating gut infections. Streptomycin is now rarely used for infections other than drug-resistant tuberculosis. It may be combined with doxycycline in the treatment of brucellosis.Resistance
The development of resistance to streptomycin is relatively common. Combining streptomycin with some other drug class to which the organism is sensitive may largely prevent this. With such treatment, the development of resistance is delayed or even prevented altogether.Tetracyclines
Following the discovery of penicillin and streptomycin, a large-scale investigation was carried out into substances that were produced by various fungi. Two important antibiotics, namely the tetracyclines, were discovered. They are very similar in chemical structure, have similar toxic effects, and are effective against the same wide range of organisms. They are:
eBook - PDF- Richard G. Wax, Kim Lewis, Abigail A. Salyers, Harry Taber, Richard G. Wax, Kim Lewis, Abigail A. Salyers, Harry Taber(Authors)
- 2007(Publication Date)
- CRC Press(Publisher)
87 Summary and Conclusions .................................................................................. 91 Acknowledgments ................................................................................................ 92 References ............................................................................................................ 92 Aminoglycoside antibiotics are positively charged carbohydrate-containing molecules that find clinical use for the treatment of infections caused by both Gram-negative and Gram-positive bacteria. The first aminoglycosides were discovered over 60 years ago and several continue to find important clinical use including gentamicin, tobramycin, amikacin, netilmicin, and streptomycin. These antibiotics target the bacterial ribosome and interfere with protein translation. Unlike other antibiotics that block translation, most aminoglycosides are bactericidal, a highly desirable feature in an antiinfective chemotherapeutic agent. The bactericidal action of ami-noglycosides is correlated with the propensity to cause misreading of the mRNA transcript resulting in the production of aberrant proteins. 72 Bacterial Resistance to Antimicrobials Resistance to the aminoglycosides can occur through decreased uptake of the drugs, aminoglycoside efflux, mutations in the rRNA and ribosomal protein, and methylation of rRNA. However, it is the presence and action of aminoglycoside-modifying enzymes that are the most relevant in the majority of resistant clinical isolates. Three distinct classes of modifying enzyme are known: the phosphotrans-ferases (APHs), the adenylyltransferases (ANTs), and the acetyltransferases (AACs). The APHs and ANTs are ATP-dependent enzymes, while the AACs require acetyl coenzyme A (acetylCoA). Members of each of these classes of enzyme are known and prevalent in both Gram-positive and Gram-negative clinical isolates.
eBook - ePub- José-Luis Capelo-Martínez, Gilberto Igrejas, José-Luis Capelo-Martínez, Gilberto Igrejas(Authors)
- 2019(Publication Date)
- Wiley(Publisher)
Part I Current Antibiotics and Their Mechanism of Action
Passage contains an image
1 Resistance to Aminoglycosides : Glycomics and the Link to the Human Gut Microbiome
Viviana G. Correia Benedita A. Pinheiro Ana Luísa Carvalho, and Angelina S. PalmaUCIBIO‐REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal1.1 Aminoglycosides as Antimicrobial Drugs
The exponential appearance of antibiotic‐resistant infections, in particular those caused by Gram‐negative pathogens, is a major public health concern. The observed decrease in the emergence of new effective antimicrobial drugs is an inevitable consequence of the use of antibiotics, and new approaches to fight infection are a matter in need of attention from the scientific community (Magiorakos et al. 2012 ). In response to this challenge, the optimization of existing drugs with known mechanisms of action and resistance, such as aminoglycosides, is an attractive approach for the development of new antimicrobials.Aminoglycosides or aminoglycoside antibiotics (AGAs) are secondary metabolites of bacteria used in the warfare against other microorganisms, which were repurposed in medicine as broad‐spectrum antibiotics in both humans and animals. This class of antibiotics has activity against Gram‐negative and Gram‐positive bacteria by targeting ribosomal RNA (rRNA), leading to protein misfolding. AGAs have predictable pharmacokinetics and often act in synergy with other antibiotics, such as beta‐lactams, making them powerful anti‐infective drugs (Hanberger et al. 2013 ). Despite their potential renal toxicity and ototoxicity and known bacterial resistance, diverse molecules of this family of antibiotics have been used in clinical practice for several decades (Thamban Chandrika and Garneau‐Tsodikova 2018
Index pages curate the most relevant extracts from our library of academic textbooks. They’ve been created using an in-house natural language model (NLM), each adding context and meaning to key research topics.
