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Mcr-1
The mobilized colistin resistance (''mcr'') gene confers plasmid-mediated resistance to colistin, one of a number of last-resort antibiotics for treating Gram-negative infections. ''mcr-1'', the original variant, is capable of horizontal transfer between different strains of a bacterial species. After discovery in November 2015 in ''E. coli'' (strain SHP45) from a pig in China it has been found in ''Escherichia coli'', ''Salmonella enterica'', ''Klebsiella pneumoniae'', '' Enterobacter aerogenes'', and ''Enterobacter cloacae''. , it has been detected in more than 30 countries on 5 continents in less than a year. Description The "mobilized colistin resistance" (''mcr-1'') gene confers plasmid-mediated resistance to colistin, a polymyxin and one of a number of last-resort antibiotics for treating infections. The gene is found in no less than ten species of the Enterobacteriaceae: ''Escherichia coli'', ''Salmonella'', ''Klebsiella pneumoniae'', '' Enterobacter aerogenes'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colistin
Colistin, also known as polymyxin E, is an antibiotic medication used as a last-resort treatment for multidrug-resistant Gram-negative infections including pneumonia. These may involve bacteria such as ''Pseudomonas aeruginosa'', ''Klebsiella pneumoniae'', or ''Acinetobacter''. It comes in two forms: colistimethate sodium can be injected into a vein, injected into a muscle, or inhaled, and colistin sulfate is mainly applied to the skin or taken by mouth. Colistimethate sodium is a prodrug; it is produced by the reaction of colistin with formaldehyde and sodium bisulfite, which leads to the addition of a sulfomethyl group to the primary amines of colistin. Colistimethate sodium is less toxic than colistin when administered parenterally. In aqueous solutions, it undergoes hydrolysis to form a complex mixture of partially sulfomethylated derivatives, as well as colistin. Resistance to colistin began to appear as of 2015. Common side effects of the injectable form include kidne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid A Phosphoethanolamine Transferase
Lipid A phosphoethanolamine transferase (EC 2.7.8.43, lipid A PEA transferase, ''LptA'', formerly EC 2.7.4.30) is an enzyme that modifies Lipid A by linkage to a phosphoethanolamine moiety. Doing so at some positions reduces the affinity to colistin and related polymyxins, resulting in reduced activity of the antimicrobial. This type of resistance is known as target modification. This type of enzyme is of special medical note, as it offers resistance to a last-resort antibiotic. The modifications also provide cross-resistance to host immunity factors, specifically antimicrobial peptides and lysozyme. EC 2.7.8.43 catalyzes one of the following three reactions: * a 1,2-diacyl-sn-glycero-3-phosphoethanolamine + H(+) + lipid A (E. coli) \rightleftharpoons a 1,2-diacyl-sn-glycerol + lipid A hexaacyl 1-(2-aminoethyl diphosphate) * a 1,2-diacyl-sn-glycero-3-phosphoethanolamine + H(+) + lipid A (E. coli) \rightleftharpoons a 1,2-diacyl-sn-glycerol + lipid A 4'-(2-aminoethyl diphosphate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymyxin
Polymyxins are antibiotics. Polymyxins B and E (also known as colistin) are used in the treatment of Gram-negative bacterial infections. They work mostly by breaking up the bacterial cell membrane. They are part of a broader class of molecules called nonribosomal peptides. They are produced in nature by Gram-positive bacteria such as ''Paenibacillus polymyxa''. Medical use Polymyxin antibiotics are relatively neurotoxic and nephrotoxic, so are usually used only as a last resort if modern antibiotics are ineffective or are contraindicated. Typical uses are for infections caused by strains of multiple drug-resistant ''Pseudomonas aeruginosa'' or carbapenemase-producing Enterobacteriaceae. Polymyxins have less effect on Gram-positive organisms, and are sometimes combined with other agents (as with trimethoprim/polymyxin) to broaden the effective spectrum. Polymyxins B are not absorbed from the gastrointestinal tract, so they are only administered orally if the goal is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kluyvera
''Kluyvera'' is a Gram negative, facultatively anaerobic bacterial and motile genus from the family of Enterobacteriaceae which have peritrichous flagella. ''Kluyvera'' occur in water, soil and sewage. ''Kluyvera'' bacteria can cause opportunistic infections in immunocompromised Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affe ... patients. Etymology The etymology of this genera is the following : ''Kluy’ver.a.'' N.L. fem. n. ''Kluyvera'', named given by Asai et al. in 1956 to honor the Dutch microbiologist A.J. Kluyver. Transference of antibiotic resistance In 2010, a gene blaCTX-M-15 responsible for coding CTX-M-15 extended-spectrum β-lactamase (ESBL) jumped from its chromosome to its plasmid, which was then shared among several bacteria. ESBL confers resistance to patho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmid-mediated Resistance
Plasmid-mediated resistance is the transfer of antibiotic resistance genes which are carried on plasmids. Plasmids possess mechanisms that ensure their independent replication as well as those that regulate their replication number and guarantee stable inheritance during cell division. By the Bacterial conjugation, conjugation process, they can stimulate lateral transfer between bacteria from various genera and kingdoms. Numerous plasmids contain addiction-inducing systems that are typically based on toxin-antitoxin factors and capable of killing daughter cells that don't inherit the plasmid during cell division. Plasmids often carry multiple antibiotic resistance genes, contributing to the spread of Multidrug resistance, multidrug-resistance (MDR). Antibiotic resistance mediated by MDR plasmids severely limits the treatment options for the infections caused by Gram-negative bacteria, especially family Enterobacteriaceae. The global spread of MDR plasmids has been enhanced by selec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimicrobial Peptide
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for antimicrobial peptides. These peptides are potent, broad spectrum antimicrobials which demonstrate potential as novel therapeutic agents. Antimicrobial peptides have been demonstrated to kill Gram negative and Gram positive bacteria, enveloped viruses, fungi and even transformed or cancerous cells. Unlike the majority of conventional antibiotics it appears that antimicrobial peptides frequently destabilize biological membranes, can form transmembrane channels, and may also have the ability to enhance immunity by functioning as immunomodulators. Structure Antimicrobial peptides are a unique and diverse group of molecules, which are divided into subgroups on the basis of their amino acid composition and structure. Antimicrobial peptides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raoultella
The genus ''Raoultella'' is composed of Gram-negative, oxidase-negative, aerobic, nonmotile, capsulated, facultatively anaerobic rods (formerly designated ''Klebsiella'') in the family Enterobacteriaceae. It is named after the French bacteriologist Didier Raoult... The existence of this genus renders the genus ''Klebsiella'' paraphyletic, and it has been repeatedly proposed to consider ''Raoultella'' a junior synonym of ''Klebsiella''. Description Members of genus ''Raoultella'' grow at 10 °C consistent with their recovery from plants, soil, and water, whereas members of ''Klebsiella'' do not grow at 10 °C and are mainly recovered from mammals' mucosae. '' Klebsiella oxytoca'' is an exception, and a proposal to classify ''K. oxytoca'' in a separate, unnamed genus has been made. It consists of species '' Raoultella electrica'', ''Raoultella ornithinolytica'', '' Raoultella planticola'' and '' Raoultella terrigena''. In human infections, Raoultella specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid A
Lipid A is a lipid component of an endotoxin held responsible for the toxicity of gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide (LPS), also called endotoxin molecule, and its hydrophobic nature allows it to anchor the LPS to the outer membrane. While its toxic effects can be damaging, the sensing of lipid A by the immune system may also be critical for the onset of immune responses to gram-negative infection, and for the subsequent successful fight against the infection. Chemical composition Lipid A consists of two glucosamine ( aminosugar) units, in a β(1→6) linkage, with attached acyl chains ("fatty acids"), and normally containing one phosphate group on each carbohydrate. The optimal immune activating lipid A structure is believed to contain 6 acyl chains. Four acyl chains attached directly to the glucosamine sugars are beta hydroxy acyl chains usually between 10 and 16 carbons in length. Two additional acyl chains are often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urinary Tract Infection
A urinary tract infection (UTI) is an infection that affects a part of the urinary tract. Lower urinary tract infections may involve the bladder (cystitis) or urethra (urethritis) while upper urinary tract infections affect the kidney (pyelonephritis). Symptoms from a lower urinary tract infection include suprapubic pain, painful urination (dysuria), frequency and urgency of urination despite having an empty bladder. Symptoms of a kidney infection, on the other hand, are more systemic and include fever or Abdominal pain, flank pain usually in addition to the symptoms of a lower UTI. Rarely, the urine may appear Hematuria, bloody. Symptoms may be vague or non-specific at the extremities of age (i.e. in patients who are very young or old). The most common cause of infection is ''Escherichia coli'', though other bacteria or fungi may sometimes be the cause. Risk factors include female anatomy, sexual intercourse, diabetes mellitus, diabetes, obesity, catheterisation, and famil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania
Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions of the United States. It borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio and the Ohio River to its west, Lake Erie and New York (state), New York to its north, the Delaware River and New Jersey to its east, and the Provinces and territories of Canada, Canadian province of Ontario to its northwest via Lake Erie. Pennsylvania's most populous city is Philadelphia. Pennsylvania was founded in 1681 through a royal land grant to William Penn, the son of William Penn (Royal Navy officer), the state's namesake. Before that, between 1638 and 1655, a southeast portion of the state was part of New Sweden, a Swedish Empire, Swedish colony. Established as a haven for religious and political tolerance, the B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Corporation. Mullis and biochemist Michael Smith (chemist), Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of Ancient DNA, ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research and forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
