Clinical data | |
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Trade names | Xylistin, Coly-Mycin M, Colobreathe, others |
AHFS/Drugs.com | Monograph |
MedlinePlus | a682860 |
License data | |
Routes of administration | Topical, by mouth, intravenous, intramuscular, inhalation |
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Pharmacokinetic data | |
Bioavailability | 0% |
Elimination half-life | 5 hours |
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CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.012.644 |
Chemical and physical data | |
Formula | C52H98N16O13 |
Molar mass | 1155.455 g·mol−1 |
3D model (JSmol) | |
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Colistin, also known as polymyxin E, is an antibiotic medication used as a last-resort treatment for multidrug-resistant Gram-negative infections including pneumonia. [7] [8] These may involve bacteria such as Pseudomonas aeruginosa , Klebsiella pneumoniae , or Acinetobacter . [9] 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. [10] Colistimethate sodium [11] 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. [12]
Common side effects of the injectable form include kidney problems and neurological problems. [8] Other serious side effects may include anaphylaxis, muscle weakness, and Clostridioides difficile-associated diarrhea. [8] The inhaled form may result in constriction of the bronchioles. [8] It is unclear if use during pregnancy is safe for the fetus. [13] Colistin is in the polymyxin class of medications. [8] It works by breaking down the cytoplasmic membrane, which generally results in bacterial cell death. [8]
Colistin was discovered in 1947 and colistimethate sodium was approved for medical use in the United States in 1970. [9] [8] It is on the World Health Organization's List of Essential Medicines. [14] The World Health Organization classifies colistin as critically important for human medicine. [15] It is available as a generic medication. [16] It is derived from bacteria of the genus Paenibacillus . [10]
Colistin has been effective in treating infections caused by Pseudomonas, Escherichia, and Klebsiella species. The following represents minimum inhibitory concentration (MIC) susceptibility data for a few medically significant microorganisms: [17] [18]
For example, colistin in combination with other drugs is used to attack P. aeruginosa biofilm infection in lungs of patients with cystic fibrosis. [19] Biofilms have a low-oxygen environment below the surface where bacteria are metabolically inactive, and colistin is highly effective in this environment. However, P. aeruginosa reside in the top layers of the biofilm, where they remain metabolically active. [20] This is because surviving tolerant cells migrate to the top of the biofilm via pili and form new aggregates via quorum sensing. [21]
Two forms of colistin are available commercially: colistin sulfate and colistimethate sodium (colistin methanesulfonate sodium, colistin sulfomethate sodium). Colistin sulfate is cationic; colistimethate sodium is anionic. Colistin sulfate is stable, whereas colistimethate sodium is readily hydrolysed to a variety of methanesulfonated derivatives. Colistin sulfate and colistimethate sodium are eliminated from the body by different routes. With respect to Pseudomonas aeruginosa, colistimethate is the inactive prodrug of colistin. The two drugs are not interchangeable.
Colistin sulfate and colistimethate sodium may both be given intravenously, but the dosing is complicated. The different labeling of the parenteral products of colistin methanesulfonate in different parts of the world was noted by Li et al. [28] Colistimethate sodium manufactured by Xellia (Colomycin injection) is prescribed in international units, whereas colistimethate sodium manufactured by Parkdale Pharmaceuticals (Coly-Mycin M Parenteral) is prescribed in milligrams of colistin base:
Because colistin was introduced into clinical practice over 50 years ago, it was never subject to the regulations that modern drugs are subject to, and therefore there is no standardised dosing of colistin and no detailed trials on pharmacology or pharmacokinetics. The optimal dosing of colistin for most infections is therefore unknown. Colomycin has a recommended intravenous dose of 1 to 2 million units three times daily for patients weighing 60 kg or more with normal renal function. Coly-Mycin has a recommended dose of 2.5 to 5 mg/kg colistin base a day, which is equivalent to 6 to 12 mg/kg colistimethate sodium per day. For a 60 kg man, therefore, the recommended dose for Colomycin is 240 to 480 mg of colistimethate sodium, yet the recommended dose for Coly-Mycin is 360 to 720 mg of colistimethate sodium. Likewise, the recommended "maximum" dose for each preparation is different (480 mg for Colomycin and 720 mg for Coly-Mycin). Each country has different generic preparations of colistin, and the recommended dose depends on the manufacturer. This complete absence of any regulation or standardisation of dose makes intravenous colistin dosing difficult for the physician. [ citation needed ]
Colistin has been used in combination with rifampicin; evidence of in vitro synergy exists, [31] [32] and the combination has been used successfully in patients. [33] There is also in vitro evidence of synergy for colistimethate sodium used in combination with other antipseudomonal antibiotics. [34]
Colistimethate sodium aerosol (Promixin; Colomycin Injection) is used to treat pulmonary infections, especially in cystic fibrosis. In the UK, the recommended adult dose is 1–2 million units (80–160 mg) nebulised colistimethate twice daily. [35] [29] Nebulized colistin has also been used to decrease severe exacerbations in patients with chronic obstructive pulmonary disease and infection with Pseudomonas aeruginosa. [36]
Resistance to colistin is rare, but has been described. As of 2017 [update] , no agreement exists about how to define colistin resistance. The Société Française de Microbiologie uses a MIC cut-off of 2 mg/L, whereas the British Society for Antimicrobial Chemotherapy sets a MIC cutoff of 4 mg/L or less as sensitive, and 8 mg/L or more as resistant. No standards for describing colistin sensitivity are given in the United States.
The first known colistin-resistance gene in a plasmid which can be transferred between bacterial strains is mcr-1 . It was found in 2011 in China on a pig farm where colistin is routinely used and became publicly known in November 2015. [37] [38] The presence of this plasmid-borne gene was confirmed starting December 2015 in South-East Asia, several European countries, [39] and the United States. [40] It is found in certain strains of the bacteria Paenibacillus polymyxa .[ citation needed ]
India reported the first detailed colistin-resistance study, which mapped 13 colistin-resistant infections recorded over 18 months. It concluded that pan-drug-resistant infections, particularly those in the bloodstream, have a higher mortality. Multiple other cases were reported from other Indian hospitals. [41] [42] Although resistance to polymyxins is generally less than 10%, it is more frequent in the Mediterranean and South-East Asia (Korea and Singapore), where colistin resistance rates are increasing. [43] Colistin-resistant E. coli was identified in the United States in May 2016. [44]
A recent review from 2016 to 2021 fount that E. coli is the dominant species harbouring mcr genes. Plasmid - mediated colistin resistance is also conferred upon other species that carry different genes resistant to antibiotics. The emergence of the mcr-9 gene is quite remarkable. [45]
Use of colistin to treat Acinetobacter baumannii infections has led to the development of resistant bacterial strains. They have also developed resistance to the antimicrobial compounds LL-37 and lysozyme, produced by the human immune system. This cross-resistance is caused by gain-of-function mutations to the pmrB gene, which controls the expression of lipid A phosphoethanolamine transferases (similar to mcr-1) located on the bacterial chromosome. [46] Similar results have been obtained with mcr-1 positive E. coli, which became better at surviving a mixture of animal antimicrobial peptides in vitro and more effective at killing infected caterpillars. [47]
Not all resistance to colistin and some other antibiotics is due to the presence of resistance genes. [48] Heteroresistance, the phenomenon wherein apparently genetically identical microbes exhibit a range of resistance to an antibiotic, [49] has been observed in some species of Enterobacter since at least 2016 [48] and was observed in some strains of Klebsiella pneumoniae in 2017–2018. [50] In some cases this phenomenon has significant clinical consequences. [50]
The main toxicities described with intravenous treatment are nephrotoxicity (damage to the kidneys) and neurotoxicity (damage to the nerves), [52] [53] [54] [55] but this may reflect the very high doses given, which are much higher than the doses currently recommended by any manufacturer and for which no adjustment was made for pre-existing renal disease. Neuro- and nephrotoxic effects appear to be transient and subside on discontinuation of therapy or reduction in dose. [56]
At a dose of 160 mg colistimethate IV every eight hours, very little nephrotoxicity is seen. [57] [58] Indeed, colistin appears to have less toxicity than the aminoglycosides that subsequently replaced it, and it has been used for extended periods up to six months with no ill effects. [59] Colistin-induced nephrotoxicity is particularly likely in patients with hypoalbuminemia. [60]
The main toxicity described with aerosolised treatment is bronchospasm, [61] which can be treated or prevented with the use of β2-adrenergic receptor agonists such as salbutamol [62] or following a desensitisation protocol. [63]
Colistin is a polycationic peptide and has both hydrophilic and lipophilic moieties. [64] These cationic regions interact with the bacterial outer membrane by displacing magnesium and calcium bacterial counter ions in the lipopolysaccharide.[ citation needed ] The hydrophobic and hydrophilic regions interact with the cytoplasmic membrane just like a detergent, solubilizing the membrane in an aqueous environment.[ citation needed ] This effect is bactericidal even in an isosmolar environment.[ citation needed ]
Colistin binds to lipopolysaccharides and phospholipids in the outer cell membrane of Gram-negative bacteria. It competitively displaces divalent cations (Ca2+ and Mg2+) from the phosphate groups of membrane lipids, which leads to disruption of the outer cell membrane, leakage of intracellular contents and bacterial death.
No clinically useful absorption of colistin occurs in the gastrointestinal tract. For systemic infection, colistin must therefore be given by injection. Colistimethate is eliminated by the kidneys, but colistin is eliminated by non-renal mechanism(s) that are as of yet not characterised. [65] [66]
Colistin was first isolated in Japan in 1949 by Y. Koyama, from a flask of fermenting Bacilluspolymyxa var. colistinus, [67] and became available for clinical use in 1959. [68]
Colistimethate sodium, a less toxic prodrug, became available for injection in 1959. In the 1980s, polymyxin use was widely discontinued because of nephro- and neurotoxicity. As multi-drug resistant bacteria became more prevalent in the 1990s, colistin started to get a second look as an emergency solution, in spite of toxicity. [69]
Colistin has also been used in agriculture, particularly in China from the 1980s onwards. Chinese production for agriculture exceeded 2700 tons in 2015. China banned colistin use for livestock growth promotion in 2016. [70]
The biosynthesis of colistin requires the use of three amino acids: threonine, leucine, and 2,4-diaminobutryic acid. The linear form of colistin is synthesized before cyclization. Non-ribosomal peptide biosynthesis begins with a loading module and then the addition of each subsequent amino acid. The subsequent amino acids are added with the help of an adenylation domain (A), a peptidyl carrier protein domain (PCP), an epimerization domain (E), and a condensation domain (C). Cyclization is accomplished by a thioesterase. [71] The first step is to have a loading domain, 6-methylheptanoic acid, associate with the A and PCP domains. Now with a C, A, and PCP domain that is associated with 2,4-diaminobutryic acid. This continues with each amino acid until the linear peptide chain is completed. The last module will have a thioesterase to complete the cyclization and form the product colistin.
Acinetobacter is a genus of Gram-negative bacteria belonging to the wider class of Gammaproteobacteria. Acinetobacter species are oxidase-negative, exhibit twitching motility, and occur in pairs under magnification.
Polymyxins are antibiotics. Polymyxins B and E 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.
Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasites.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes. P. aeruginosa is able to selectively inhibit various antibiotics from penetrating its outer membrane - and has high resistance to several antibiotics. According to the World Health Organization P. aeruginosa poses one of the greatest threats to humans in terms of antibiotic resistance.
Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta-lactam antibiotics drug class, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.
Imipenem is a synthetic β-lactam antibiotic belonging to the carbapenems chemical class. developed by Merck scientists Burton Christensen, William Leanza, and Kenneth Wildonger in the mid-1970s. Carbapenems are highly resistant to the β-lactamase enzymes produced by many multiple drug-resistant Gram-negative bacteria, thus playing a key role in the treatment of infections not readily treated with other antibiotics. It is usually administered through intravenous injection.
Amikacin is an antibiotic medication used for a number of bacterial infections. This includes joint infections, intra-abdominal infections, meningitis, pneumonia, sepsis, and urinary tract infections. It is also used for the treatment of multidrug-resistant tuberculosis. It is used by injection into a vein using an IV or into a muscle.
Acinetobacter baumannii is a typically short, almost round, rod-shaped (coccobacillus) Gram-negative bacterium. It is named after the bacteriologist Paul Baumann. It can be an opportunistic pathogen in humans, affecting people with compromised immune systems, and is becoming increasingly important as a hospital-derived (nosocomial) infection. While other species of the genus Acinetobacter are often found in soil samples, it is almost exclusively isolated from hospital environments. Although occasionally it has been found in environmental soil and water samples, its natural habitat is still not known.
Polypeptide antibiotics are a chemically diverse class of anti-infective and antitumor antibiotics containing non-protein polypeptide chains. Examples of this class include actinomycin, bacitracin, colistin, and polymyxin B. Actinomycin-D has found use in cancer chemotherapy. Most other polypeptide antibiotics are too toxic for systemic administration, but can safely be administered topically to the skin as an antiseptic for shallow cuts and abrasions.
Arbekacin (INN) is a semisynthetic aminoglycoside antibiotic which was derived from kanamycin. It is primarily used for the treatment of infections caused by multi-resistant bacteria including methicillin-resistant Staphylococcus aureus (MRSA). Arbekacin was originally synthesized from dibekacin in 1973 by Hamao Umezawa and collaborators. It has been registered and marketed in Japan since 1990 under the trade name Habekacin. Arbekacin is no longer covered by patent and generic versions of the drug are also available under such trade names as Decontasin and Blubatosine.
Multidrug resistant Gram-negative bacteria are a type of Gram-negative bacteria with resistance to multiple antibiotics. They can cause bacteria infections that pose a serious and rapidly emerging threat for hospitalized patients and especially patients in intensive care units. Infections caused by MDR strains are correlated with increased morbidity, mortality, and prolonged hospitalization. Thus, not only do these bacteria pose a threat to global public health, but also create a significant burden to healthcare systems.
Eravacycline is a synthetic halogenated tetracycline class antibiotic by Tetraphase Pharmaceuticals. It is closely related to tigecycline. It has a broad spectrum of activity including many multi-drug resistant strains of bacteria. Phase III studies in complicated intra-abdominal infections (cIAI) and complicated urinary tract infections (cUTI) were recently completed with mixed results. Eravacycline was granted fast track designation by the FDA and is currently available in USA.
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 from a pig in China it has been found in Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, Enterobacter aerogenes, and Enterobacter cloacae. As of 2017, it has been detected in more than 30 countries on 5 continents in less than a year.
ESKAPE is an acronym comprising the scientific names of six highly virulent and antibiotic resistant bacterial pathogens including: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. The acronym is sometimes extended to ESKAPEE to include Escherichia coli. This group of Gram-positive and Gram-negative bacteria can evade or 'escape' commonly used antibiotics due to their increasing multi-drug resistance (MDR). As a result, throughout the world, they are the major cause of life-threatening nosocomial or hospital-acquired infections in immunocompromised and critically ill patients who are most at risk. P. aeruginosa and S. aureus are some of the most ubiquitous pathogens in biofilms found in healthcare. P. aeruginosa is a Gram-negative, rod-shaped bacterium, commonly found in the gut flora, soil, and water that can be spread directly or indirectly to patients in healthcare settings. The pathogen can also be spread in other locations through contamination, including surfaces, equipment, and hands. The opportunistic pathogen can cause hospitalized patients to have infections in the lungs, blood, urinary tract, and in other body regions after surgery. S. aureus is a Gram-positive, cocci-shaped bacterium, residing in the environment and on the skin and nose of many healthy individuals. The bacterium can cause skin and bone infections, pneumonia, and other types of potentially serious infections if it enters the body. S. aureus has also gained resistance to many antibiotic treatments, making healing difficult. Because of natural and unnatural selective pressures and factors, antibiotic resistance in bacteria usually emerges through genetic mutation or acquires antibiotic-resistant genes (ARGs) through horizontal gene transfer - a genetic exchange process by which antibiotic resistance can spread.
Murepavadin also known as POL7080 is a Pseudomonas specific peptidomimetic antibiotic. It is a synthetic cyclic beta hairpin peptidomimetic based on the cationic antimicrobial peptide protegrin I (PG-1) and the first example of an outer membrane protein-targeting antibiotic class with a novel, nonlytic mechanism of action, highly active and selective against the protein transporter LptD of Pseudomonas aeruginosa. In preclinical studies the compound was highly active on a broad panel of clinical isolates including multi-drug resistant Pseudomonas bacteria with outstanding in vivo efficacy in sepsis, lung, and thigh infection models. Intravenous murepavadin is in development for the treatment of bacterial hospital-acquired pneumonia and bacterial ventilator-associated pneumonia due to Pseudomonas aeruginosa.
Cefiderocol, sold under the brand name Fetroja among others, is an antibiotic used to treat complicated urinary tract infections when no other options are available. It is indicated for the treatment of multi-drug-resistant Gram-negative bacteria including Pseudomonas aeruginosa. It is given by injection into a vein.
The Center for Innovative Phage Applications and Therapeutics (IPATH) is the first phage therapy center in North America, founded in the UC San Diego School of Medicine in June 2018, with seed funding from UC San Diego Chancellor Pradeep Khosla. The center was founded by Steffanie A. Strathdee and Robert "Chip" Schooley, both professors at UC San Diego School of Medicine. The center currently treats patients with life-threatening multi-drug resistant infections with phage therapy, on a case-by-case basis, through the Food and Drug Administration's (FDA's) compassionate use program. IPATH aims to initiate phase I/II phage therapy clinical trials, focusing on patients with cystic fibrosis and infections related to implantable hardware, such as pacemakers and prosthetic joints. The first planned clinical trial is set to look at otherwise healthy cystic fibrosis patients that are shedding Pseudomonas aeruginosa.
Sulbactam/durlobactam, sold under the brand name Xacduro, is a co-packaged medication used for the treatment of bacterial pneumonia caused by Acinetobacter baumannii-calcoaceticus complex. It contains sulbactam, a beta-lactam antibacterial and beta-lactamase inhibitor; and durlobactam, a beta-lactamase inhibitor.
SPR741 is an experimental antibiotic related to Polymyxin B. It shows activity against a number of bacterial pathogens, especially Acinetobacter baumannii and Klebsiella pneumoniae, acting as an antibiotic adjuvant which disrupts the outer membrane of Gram-negative bacteria and allows other antibiotics to more effectively penetrate into the cell.