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Extended-spectrum Beta-lactamase
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. Beta-lactam antibiotics are typically used to target a broad spectrum of gram-positive and gram-negative bacteria. Beta-lactamases produced by gram-negative bacteria are usually secreted, especially when antibiotics are present in the environment. Structure The structure of a ''Streptomyces'' serine β-lactamase (SBLs) is given by . The alpha-beta fold ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces Albus
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''Streptomyces albus'' is a bacterial species from which the pseudodisaccharide aminoglycoside salbostatin was isolated. ''S. albus'' is known to produce white aerial mycelium. References Further reading * External linksType strain of ''Streptomyces albus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase albus Albus may refer to: * Albus (surname) * Albinus (cognomen), or Albus, a Latin surname * Albus (coin), ''groschen'' coin of the Holy Roman Empire * Albus, a Geomantic figure * 'Albus', a cultivar of Rosemary Entertainment * Albus Dumbledore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-positive
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage degrades the outer membrane of gram-negative cells, making the cell wall more porous and incapable of retaining the crystal violet stain. Their peptidoglycan layer is much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane, causing them to take up the counterstain (saf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceftizoxime
Ceftizoxime is a third-generation cephalosporin available for parenteral administration. Unlike other third-generation cephalosporins, the whole C-3 side chain in ceftizoxime has been removed to prevent deactivation by hydrolytic enzymes. It rather resembles cefotaxime in its properties, but is not subject to metabolism. It was removed from the US Market in 2007. Synthesis Injectable third generation cephalosporin antibiotic related to cefotaxime, q.v. } (right to left). , - , ''quo errat demonstrator'', , where the prover errs, , A pun on "quod erat demonstrandum" , - , ''quo fata ferunt'', , where the fates bear us to, , motto of Bermuda , - , ''quo non ascendam'' , , to what heights can I ... Exhibits broad spectrum activity and resistance to β-lactamase hydrolysis. References Cephalosporin antibiotics Thiazoles {{antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteus Mirabilis
''Proteus mirabilis'' is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It shows swarming motility and urease activity. ''P. mirabilis'' causes 90% of all ''Proteus'' infections in humans. It is widely distributed in soil and water. ''Proteus mirabilis'' can migrate across the surface of solid media or devices using a type of cooperative group motility called swarming. ''Proteus mirabilis'' is most frequently associated with infections of the urinary tract, especially in complicated or catheter-associated urinary tract infections. Diagnosis An alkaline urine sample is a possible sign of ''P. mirabilis''. It can be diagnosed in the lab due to characteristic swarming motility, and inability to metabolize lactose (on a MacConkey agar plate, for example). Also ''P. mirabilis'' produces a very distinct fishy odor. Disease This rod-shaped bacterium has the ability to produce high levels of urease, which hydrolyzes urea to ammonia (NH3), so makes the urine more a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella
''Salmonella'' is a genus of rod-shaped (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two species of ''Salmonella'' are ''Salmonella enterica'' and ''Salmonella bongori''. ''S. enterica'' is the type species and is further divided into six subspecies that include over 2,600 serotypes. ''Salmonella'' was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon. ''Salmonella'' species are non-spore-forming, predominantly motile enterobacteria with cell diameters between about 0.7 and 1.5 μm, lengths from 2 to 5 μm, and peritrichous flagella (all around the cell body, allowing them to move). They are chemotrophs, obtaining their energy from oxidation and reduction reactions, using organic sources. They are also facultative anaerobes, capable of generating ATP with oxygen ("aerobically") when it is available, or using other electron acceptors or fermentation ("anaerobically") when oxygen is not available. ''Salmonella'' spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrobacter Freundii
''Citrobacter freundii'' is a species of facultative anaerobic Gram-negative bacteria of the family Enterobacteriaceae which currently consists of 13 recognized species. These bacteria have a rod shape with a typical length of 1–5 μm. Most ''C. freundii'' cells have several flagella used for locomotion, although some non-motile taxa do not. ''C. freundii'' is a soil-dwelling microorganism, but can also be found in water, sewage, food, and the intestinal tracts of animals and humans. The genus Citrobacter was discovered in 1932 by Werkman and Gillen. Cultures of ''C. freundii'' were isolated and identified in the same year from soil extracts. Cell morphology and features Exopolysaccharides from ''C. freundii'' target the hydroxyl radical, demonstrating antioxidant activity. These antioxidant properties are related to many different physical and chemical properties. ''C. freundii'' can also have a positive impact when it comes to the treatment of some cancers; specifically, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterobacter Cloacae
''Enterobacter cloacae'' is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium. Microbiology In microbiology labs, ''E. cloacae'' is frequently grown at 30 °C on nutrient agar or at 35 °C in tryptic soy broth. It is a rod-shaped, Gram-negative bacterium, is facultatively anaerobic, and bears peritrichous flagella. It is oxidase-negative and catalase-positive. Industrial use ''Enterobacter cloacae'' has been used in a bioreactor-based method for the biodegradation of explosives and in the biological control of plant diseases. ''Enterobacter cloacae'' strain MBB8 isolated from the Gulf of Mannar, India was reported to degrade poly vinyl alcohol (PVA). This was the first report of a PVA degrader from the Enterobacter genus. ''E. cloacae'' was also reported to produce exopolysaccharide (EPS) as high as 18.3g/L. GC-MS analysis of ''E. cloacae'' EPS showed the presence of glucose and mannose in the molar ratio of 1: 1.5e−2. Safe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Resistance
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Those bacteria that are considered extensively drug resistant (XDR) or totally drug-resistant (TDR) are sometimes called "superbugs".A.-P. Magiorakos, A. Srinivasan, R. B. Carey, Y. Carmeli, M. E. Falagas, C. G. Giske, S. Harbarth, J. F. Hinndler ''et al''Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria... Clinical Microbiology and Infection, Vol 8, Iss. 3 first published 27 July 2011 ia Wiley Online Library Retrieved 28 August 2020 Although antimicrobial resistance is a naturally-occurring process, it is often the result of improper usage of the drugs and management of the infections. Antibiotic resistance is a major subset ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methicillin
Methicillin (USAN), also known as meticillin (INN), is a narrow-spectrum β-lactam antibiotic of the penicillin class. Methicillin was discovered in 1960. Medical uses Compared to other penicillins that face antimicrobial resistance due to β-lactamase, it is less active, can be administered only parenterally, and has a higher frequency of interstitial nephritis, an otherwise-rare adverse effect of penicillins. However, selection of methicillin depended on the outcome of susceptibility testing of the sampled infection, and since it is no longer produced, it is also not routinely tested for any more. It also served a purpose in the laboratory to determine the antibiotic sensitivity of ''Staphylococcus aureus'' to other penicillins facing β-lactam resistance; this role has now been passed on to other penicillins, namely ''cloxacillin'', as well as genetic testing for the presence of ''mecA'' gene by '' PCR''. Spectrum of activity At one time, methicillin was used to tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β-lactam
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, 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 Beta-lactam antibiotic, 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. Clinical significance The β-lactam ring is part of the core structure of several antibiotic families, the principal ones being the penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called β-lactam antibiotics. Nearly all of these antibiotics work by inhibiting bacterial cell wall biosynthesis. This has a lethal effect on bacteria, although any given bacteria population will typically contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNase Z
TRNase Z (, ''3 tRNase'', ''tRNA 3 endonuclease'', ''RNase Z'', ''3' tRNase'') is an enzyme that, among other things, catalyses the reactions involved in the maturation of tRNAs. Here, it endonucleolytically cleaves the RNA and removes extra 3' nucleotides from the tRNA precursor, generating the 3' termini of tRNAs. A 3'-hydroxy group is left at the tRNA terminus and a 5'-phosphoryl {{unreferenced, date=May 2015 A phosphoryl group is the chemical ion or radical: P+O32−, containing phosphorus and oxygen. (The correct chemical name for this −PO32− group is phosphonato, and phosphono for −PO3H2; as ''phosphoryl'' in ch ... group is left at the trailer molecule. Similarly, it processes tRNA-like molecules such as mascRNA. The enzyme does not use a cofactor. References External links * {{Portal bar, Biology, border=no EC 3.1.26 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Delhi Metallo-beta-lactamase 1
NDM-1 is an enzyme that makes bacteria resistant to a broad range of beta-lactam antibiotics. These include the antibiotics of the carbapenem family, which are a mainstay for the treatment of antibiotic-resistant bacterial infections. The gene for NDM-1 is one member of a large gene family that encodes beta-lactamase enzymes called carbapenemases. Bacteria that produce carbapenemases are often referred to in the news media as " superbugs" because infections caused by them are difficult to treat. Such bacteria are usually sensitive only to polymyxins and tigecycline. NDM-1 was first detected in a ''Klebsiella pneumoniae'' isolate from a Swedish patient of Indian origin in 2008. It was later detected in bacteria in India, Pakistan, the United Kingdom, the United States, Canada, Japan, and Egypt. The most common bacteria that make this enzyme are gram-negative such as ''Escherichia coli'' and ''Klebsiella pneumoniae'', but the gene for NDM-1 can spread from one strain of bacteria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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