Clinical data | |
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Trade names | Bactroban, others |
Other names | muciprocin [1] |
AHFS/Drugs.com | Monograph |
MedlinePlus | a688004 |
License data | |
Pregnancy category |
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Routes of administration | Topical |
ATC code | |
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Pharmacokinetic data | |
Protein binding | 97% |
Elimination half-life | 20 to 40 minutes |
Identifiers | |
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CAS Number | |
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DrugBank | |
ChemSpider | |
UNII | |
KEGG | |
ChEBI | |
ChEMBL | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.106.215 |
Chemical and physical data | |
Formula | C26H44O9 |
Molar mass | 500.629 g·mol−1 |
3D model (JSmol) | |
Melting point | 77 to 78 °C (171 to 172 °F) |
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Mupirocin, sold under the brand name Bactroban among others, is a topical antibiotic useful against superficial skin infections such as impetigo or folliculitis. [5] [6] [7] It may also be used to get rid of methicillin-resistant S. aureus (MRSA) when present in the nose without symptoms. [6] Due to concerns of developing resistance, use for greater than ten days is not recommended. [7] It is used as a cream or ointment applied to the skin. [6]
Common side effects include itchiness and rash at the site of application, headache, and nausea. [6] Long term use may result in increased growth of fungi. [6] Use during pregnancy and breastfeeding appears to be safe. [6] Mupirocin is chemically a carboxylic acid. [8] It works by blocking a bacteria's ability to make protein, which usually results in bacterial death. [6]
Mupirocin was initially isolated in 1971 from Pseudomonas fluorescens . [9] It is on the World Health Organization's List of Essential Medicines. [10] In 2021, it was the 203rd most commonly prescribed medication in the United States, with more than 2 million prescriptions. [11] [12] It is available as a generic medication. [13]
Mupirocin is used as a topical treatment for bacterial skin infections (for example, boils, impetigo, or open wounds), which are typically due to infection by Staphylococcus aureus or Streptococcus pyogenes. It is also useful in the treatment of superficial methicillin-resistant Staphylococcus aureus (MRSA) infections. [14] Mupirocin is inactive for most anaerobic bacteria, mycobacteria, mycoplasma, chlamydia, yeast, and fungi. [15]
Intranasal mupirocin before surgery is effective for prevention of post-operative wound infection with Staphylcoccus aureus and preventative intranasal or catheter-site treatment is effective for reducing the risk of catheter site infection in persons treated with chronic peritoneal dialysis. [16]
Shortly after the clinical use of mupirocin began, strains of Staphylococcus aureus that were resistant to mupirocin emerged, with nares clearance rates of less than 30% success. [17] [18] Two distinct populations of mupirocin-resistant S. aureus were isolated. One strain possessed low-level resistance (MuL: MIC = 8–256 mg/L), and another possessed high-level resistance (MuH: MIC > 256 mg/L). [17] Resistance in the MuL strains is probably due to mutations in the organism's wild-type isoleucyl-tRNA synthetase (IleS). In E. coli IleS, a single amino acid mutation was shown to alter mupirocin resistance. [19] MuH is linked to the acquisition of a separate Ile synthetase gene, MupA. [20] Mupirocin is not a viable antibiotic against MuH strains. Other antibiotic agents, such as azelaic acid, nitrofurazone, silver sulfadiazine, and ramoplanin have been shown to be effective against MuH strains. [17]
Most strains of Cutibacterium acnes , a causative agent in the skin disease acne vulgaris, are naturally resistant to mupirocin. [21]
Most strains of Pseudomonas fluorescens are also resistant to mupirocin as they produce the antibiotic and it's possible other species of Pseudomonas may be resistant as well. [ citation needed ]
The mechanism of action of mupirocin differs from other clinical antibiotics, rendering cross-resistance to other antibiotics unlikely. [17] However, the MupA gene may co-transfer with other antibacterial resistance genes. This has been observed already with resistance genes for triclosan, tetracycline, and trimethoprim. [17] It may also result in overgrowth of non-susceptible organisms.[ citation needed ]
A second type of high-level resistant synthetase was discovered in 2012 and termed MupB. It was found in a Canadian MRSA isolate "MUP87" and is probably located on a nonconjugative plasmid. [22]
Pseudomonic acid (mupirocin) inhibits isoleucine—tRNA ligase in bacteria, [14] leading to depletion of isoleucyl-tRNA and accumulation of the corresponding uncharged tRNA. Depletion of isoleucyl-tRNA results in inhibition of protein synthesis. The uncharged form of the tRNA binds to the aminoacyl-tRNA binding site of ribosomes, triggering the formation of (p)ppGpp, which in turn inhibits RNA synthesis. [23] The combined inhibition of protein synthesis and RNA synthesis results in bacteriostasis. This mechanism of action is shared with furanomycin, an analog of isoleucine. [24]
Inhibition of the tRNA ligase/synthase is brought by the structural similarity between the molecule's monic acid "head" part and isoleucyl-adenylate (Ile-AMS). The unique 9-hydroxynonanoic acid "tail" wraps around the enzyme and further stabilizes the complex, keeping the catalytic part stuck. [25] Mupirocin is able to bind to bacterial and archaeal versions of the enzyme, but not eukaryotic versions. [26]
Mupirocin is a mixture of several pseudomonic acids, with pseudomonic acid A (PA-A) constituting greater than 90% of the mixture. Also present in mupirocin are pseudomonic acid B with an additional hydroxyl group at C8, [29] pseudomonic acid C with a double bond between C10 and C11, instead of the epoxide of PA-A, [30] and pseudomonic acid D with a double bond at C4` and C5` in the 9-hydroxy-nonanoic acid portion of mupirocin. [31]
The 74 kb mupirocin gene cluster contains six multi-domain enzymes and twenty-six other peptides (Table 1). [27] Four large multi-domain type I polyketide synthase (PKS) proteins are encoded, as well as several single function enzymes with sequence similarity to type II PKSs. [27] Therefore, it is believed that mupirocin is constructed by a mixed type I and type II PKS system. The mupirocin cluster exhibits an atypical acyltransferase (AT) organization, in that there are only two AT domains, and both are found on the same protein, MmpC. These AT domains are the only domains present on MmpC, while the other three type I PKS proteins contain no AT domains. [27] The mupirocin pathway also contains several tandem acyl carrier protein doublets or triplets. This may be an adaptation to increase the throughput rate or to bind multiple substrates simultaneously. [27]
Pseudomonic acid A is the product of an esterification between the 17C polyketide monic acid and the 9C fatty acid 9-hydroxy-nonanoic acid. The possibility that the entire molecule is assembled as a single polyketide with a Baeyer-Villiger oxidation inserting an oxygen into the carbon backbone has been ruled out because C1 of monic acid and C9' of 9-hydroxy-nonanoic acid are both derived from C1 of acetate. [32]
Gene | Function |
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mupA | FMNH2 dependent oxygenase |
mmpA | KS ACP KS KR ACP KS ACP ACP |
mupB | 3-oxoacyl-ACP synthase |
mmpB | KS DH KR ACP ACP ACP TE |
mmpC | AT AT |
mmpD | KS DH KR MeT ACP KS DH KR ACP KS DH KR MeT ACP KS KR ACP |
mupC | NADH/NADPH oxidoreductase |
macpA | ACP |
mupD | 3-oxoacyl-ACP reductase |
mupE | enoyl reductase |
macpB | ACP |
mupF | KR |
macpC | ACP |
mupG | 3-oxoacyl-ACP synthase I |
mupH | HMG-CoA synthase |
mupJ | enoyl-CoA hydratase |
mupK | enoyl-CoA hydratase |
mmpE | KS hydrolase |
mupL | putative hydrolase |
mupM | isoleucyl-tRNA synthase |
mupN | phosphopantetheinyl transferase |
mupO | cytochrome P450 |
mupP | unknown |
mupQ | acyl-CoA synthase |
mupS | 3-oxoacyl-ACP reductase |
macpD | ACP |
mmpF | KS |
macpE | ACP |
mupT | ferredoxin dioxygenase |
mupU | acyl-CoA synthase |
mupV | oxidoreductase |
mupW | dioxygenase |
mupR | N-AHL-responsive transcriptional activator |
mupX | amidase/hydrolase |
mupI | N-AHL synthase |
Biosynthesis of the 17C monic acid unit begins on MmpD (Figure 1). [27] One of the AT domains from MmpC may transfer an activated acetyl group from acetyl-Coenzyme A (CoA) to the first ACP domain. The chain is extended by malonyl-CoA, followed by a SAM-dependent methylation at C12 (see Figure 2 for PA-A numbering) and reduction of the B-keto group to an alcohol. The dehydration (DH) domain in module 1 is predicted to be non-functional due to a mutation in the conserved active site region. Module 2 adds another two carbons by the malonyl-CoA extender unit, followed by ketoreduction (KR) and dehydration. Module three adds a malonyl-CoA extender unit, followed by SAM-dependent methylation at C8, ketoreduction, and dehydration. Module 4 extends the molecule with a malonyl-CoA unit followed by ketoreduction.[ citation needed ]
Assembly of monic acid is continued by the transfer of the 12C product of MmpD to MmpA. [27]
The keto group at C3 is replaced with a methyl group in a multi-step reaction (Figure 3). MupG begins by decarboxylating a malonyl-ACP. The alpha carbon of the resulting acetyl-ACP is linked to C3 of the polyketide chain by MupH. This intermediate is dehydrated and decarboxylated by MupJ and MupK, respectively. [27]
The formation of the pyran ring requires many enzyme-mediated steps (Figure 4). The double bond between C8 and C9 is proposed to migrate to between C8 and C16. [28] Gene knockout experiments of mupO, mupU, mupV, and macpE have eliminated PA-A production. [28] PA-B production is not removed by these knockouts, demonstrating that PA-B is not created by hydroxylating PA-A. A knockout of mupW eliminated the pyran ring, identifying MupW as being involved in ring formation. [28]
The epoxide of PA-A at C10-11 is believed to be inserted after pyran formation by a cytochrome P450 such as MupO. [27] A gene knockout of mupO abolished PA-A production but PA-B, which also contains the C10-C11 epoxide, remained. [28]
The nine-carbon fatty acid 9-hydroxy-nonanoic acid (9-HN) is derived as a separate compound and later esterified to monic acid to form pseudomonic acid. 13C labeled acetate feeding has shown that C1-C6 are constructed with acetate in the canonical fashion of fatty acid synthesis. C7' shows only C1 labeling of acetate, while C8' and C9' show a reversed pattern of 13C labeled acetate. [32] It is speculated that C7-C9 arises from a 3-hydroxypropionate starter unit, which is extended three times with malonyl-CoA and fully reduced to yield 9-HN. It has also been suggested that 9-HN is initiated by 3-hydroxy-3-methylglutaric acid (HMG). This latter theory was not supported by feeding of [3-14C] or [3,6-13C2]-HMG. [33]
It is proposed that MmpB to catalyze the synthesis of 9-HN (Figure 5). MmpB contains a KS, KR, DH, 3 ACPs, and a thioesterase (TE) domain. [27] It does not contain an enoyl reductase (ER) domain, which would be required for the complete reduction to the nine-carbon fatty acid. MupE is a single-domain protein that shows sequence similarity to known ER domains and may complete the reaction. [27]
Staphylococcus aureus is a gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe, meaning that it can grow without oxygen. Although S. aureus usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. S. aureus is one of the leading pathogens for deaths associated with antimicrobial resistance and the emergence of antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA). The bacterium is a worldwide problem in clinical medicine. Despite much research and development, no vaccine for S. aureus has been approved.
Methicillin-resistant Staphylococcus aureus (MRSA) is a group of gram-positive bacteria that are genetically distinct from other strains of Staphylococcus aureus. MRSA is responsible for several difficult-to-treat infections in humans. It caused more than 100,000 deaths worldwide attributable to antimicrobial resistance in 2019.
Methicillin (USAN), also known as meticillin (INN), is a narrow-spectrum β-lactam antibiotic of the penicillin class.
Pseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus; 16S rRNA analysis as well as phylogenomic analysis has placed P. fluorescens in the P. fluorescens group within the genus, to which it lends its name.
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Fusidic acid, sold under the brand name Fucidin among others, is a steroid antibiotic that is often used topically in creams or ointments and eyedrops but may also be given systemically as tablets or injections. As of October 2008, the global problem of advancing antimicrobial resistance has led to a renewed interest in its use.
Vancomycin-resistant Staphylococcus aureus (VRSA) are strains of Staphylococcus aureus that have acquired resistance to the glycopeptide antibiotic vancomycin. Bacteria can acquire resistant genes either by random mutation or through the transfer of DNA from one bacterium to another. Resistance genes interfere with the normal antibiotic function and allow bacteria to grow in the presence of the antibiotic. Resistance in VRSA is conferred by the plasmid-mediated vanA gene and operon. Although VRSA infections are uncommon, VRSA is often resistant to other types of antibiotics and a potential threat to public health because treatment options are limited. VRSA is resistant to many of the standard drugs used to treat S. aureus infections. Furthermore, resistance can be transferred from one bacterium to another.
Daptomycin, sold under the brand name Cubicin among others, is a lipopeptide antibiotic used in the treatment of systemic and life-threatening infections caused by Gram-positive organisms.
Staphylococcus haemolyticus is a member of the coagulase-negative staphylococci (CoNS). It is part of the skin flora of humans, and its largest populations are usually found at the axillae, perineum, and inguinal areas. S. haemolyticus also colonizes primates and domestic animals. It is a well-known opportunistic pathogen, and is the second-most frequently isolated CoNS. Infections can be localized or systemic, and are often associated with the insertion of medical devices. The highly antibiotic-resistant phenotype and ability to form biofilms make S. haemolyticus a difficult pathogen to treat. Its most closely related species is Staphylococcus borealis.
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.
Pristinamycin (INN), also spelled pristinamycine, is an antibiotic used primarily in the treatment of staphylococcal infections, and to a lesser extent streptococcal infections. It is a streptogramin group antibiotic, similar to virginiamycin, derived from the bacterium Streptomyces pristinaespiralis. It is marketed in Europe by Sanofi-Aventis under the trade name Pyostacine.
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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.
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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.
Staphylococcus is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. Staphylococcus species are facultative anaerobic organisms.
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