Мупироцин

Описание

Mupirocin (pseudomonic acid A) is an antibiotic produced by Pseudomonas fluorescens. It is useful in the treatment of dermal infections, especially those involving S. aureus and S. epidermidis.

Химические свойства

White Crystalline Solid

Использование

Mupirocin, is a major component of the pseudomonic acid, an antibiotic complex produced by Pseudomonas fluorescens NCIB 10586. Topical antibacterial.

Показания

Mupirocin (Bactroban, Centany) is a topical antibiotic produced by fermented Pseudomonas fluorescens. It has a narrow spectrum of activity, mostly against gram-positive aerobic bacteria (including Staphylococcus and methicillin-resistant Staphylococcus) and many strains of Streptococcus. It is also active against some gram-negative aerobic bacteria but is inactive against anaerobes, Chlamydia, and fungi. It has proved equal in efficacy in the treatment of impetigo when compared with oral erythromycin, with fewer adverse side effects.
Mupirocin does not interfere with wound healing. It is active only on topical administration and is converted to an inert molecule on systemic administration. Prolonged use of mupirocin increases the risk of evolution of resistant organisms. Themechanism of action has not yet been fully classified, but it does differ from other available antiinfective agents, and there is little chance of cross-resistance developing. Also, unlike many other topical antibiotics, it rarely causes allergic sensitization.

Определение

ChEBI: An alpha,beta-unsaturated ester resulting from the formal condensation of the alcoholic hydroxy group of 9-hydroxynonanoic acid with the carboxy group of (2E)-4-[(2S)-tetrahydro-2 -pyran-2-yl]-3-methylbut-2-enoic acid in which the tetrahydropyranyl ring is substituted at positions 3 and 4 by hydroxy groups and at position 5 by a {(2S,3S)-3-[(2S,3S)-3-hydro ybutan-2-yl]oxiran-2-yl}methyl group. Originally isolated from the Gram-negative bacterium Pseudomonas fluorescens, it is used as a topical antibiotic for the treatment of Gram-positive bacterial infections.

Антимикробная активность

It is active against staphylococci and streptococci, but also Neisseria and Haemophilus spp. Enterococcus faecalis tends to be sensitive whereas E. faecium is usually resistant. Activity against Staph. aureus is affected by inoculum such that a 10-fold increase in the inoculum causes doubling of the minimum inhibitory concentration (MIC) in vitro. Activity also decreases as pH increases above the normal skin pH of 5.5.

Приобретенная устойчивость

Before the introduction of mupirocin, resistance in Staph. aureus was uncommon, with a natural mutation frequency of 1 in 109. However, shortly after the agent was introduced, mupirocin-resistant strains began to emerge. They are of two types: low level (MIC 8–256 mg/mL) and high level (MIC >256 mg/mL).
High-level resistance, in contrast, is linked to the acquisition of a transmissible resistance gene MupA that may co-transfer with other antimicrobial resistance genes. Strains that express MupA are not clinically susceptible to mupirocin.
Several studies suggest that widespread use of prophylactic mupirocin may result in increased levels of resistance. In Canada increasing use of mupirocin across the country led to high-level mupirocin resistance, rising from 1.6% to 7% over a 9-year period.

Фармацевтические приложения

Mupirocin is an antimicrobial substance originally derived from Pseudomonas fluorescens. It is a mixture of pseudomonic acids with more than 90% of the commercial product being pseudomonic acid A.
It has activity predominantly against Gram-positive bacteria and its main use is as a topical agent for the eradication of carriage of methicillin-resistant Staphylococcus aureus (MRSA). It is also used as a topical treatment for superficial skin infections caused by Grampositive organisms such as impetigo.

Фармакокине?тика

Following parenteral administration, mupirocin is rapidly destroyed by non-specific esterases (possibly in renal or liver tissues since it is reasonably stable in blood) to inactive monic acid and its conjugates. It is strongly protein bound. About 0.25% is absorbed from intact skin. The skin ointment, but not the cream, contains polyethylene glycol, which may be absorbed significantly when applied to open wounds or damaged skin, including burns.

Клиническое использование

Mupirocin is mainly used as a nasal cream as part of the regimen to decolonize patients who have been found to carry methicillin-resistant Staph. aureus. It can also be applied to tracheostomy, gastrostomy and other sites that are frequently colonized with MRSA.
The use of mupirocin as a means of controlling outbreaks of infection due to MRSA appears to be of only marginal benefit in an endemic situation.
A Cochrane Review of nine randomized controlled trials of use of mupirocin to prevent subsequent Staph. aureus infections in nasal carriers of the organism found a statistically significant reduction in such infections at any site. A small study of local therapy to reduce the risk of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD) found that mupirocin applied three times weekly to the dialysis catheter exit site resulted in a 92% reduction in the rate of peritonitis

Побочные эффекты

Topical applications are well tolerated. Conjunctival application is contraindicated as it may cause irritation. Minor side effects such as irritation and unpleasant or abnormal taste have been recorded for very few patients following nasal application.
Polyethylene glycol from the ointment base may, if absorbed from application to open wounds or damaged skin, cause renal toxicity.