Mupirocin

Structure-activity relationships 9.4 Mupirocin (pseudomonic acid A)... 

Mupirocin (Fig. 5.14E) is the main fermentation product obtained ftomPs.fluorescens. 

Fig. 5.14 Miscellaneous antibiotics A, chloramphenicol B, fusidic acid C, lincomycin D, clindamycin E, mupirocin (pseudomonic acid A).

Other pseudomonic acids (B, C, D) are also produced. Mupirocin is active predominantly against staphylococci and most streptococci, but Enterococcus faecalis and Gramnegative bacilli are resistant There is also evidence of plasmid-mediated mupirocin resistance in some chnical isolates of Staph, aureus. 

Mupirocin is employed topically in eradicating nasal and skin carriage of staphylococci, including methicilhn-resistantS to/)/ , colonization. 

Bacterial ribosome function Aminoglycosides Tetracyclines Chloramphenicol Macrolides, azalides Fusidic acid Mupirocin Distort SOS ribosomal subunit Block SOS ribosomal subunit Inhibits peptidyl transferase Block translocation Inhibits elongation factor Inhibits isoleucyl-tRNA synthesis No action on 40S subunit Excluded by mammalian cells No action on mammalian equivalent No action on mammalian equivalent Excluded by mammalian cells No action on mammalian equivalent... 

The target of mupirocin is one of a group of enzymes which couple amino acids to their respective tRNAs for delivery to the ribosome and incorporation into protein. The particular enzyme inhibited by mupirocin is involved in producing isoleucyl-tRNA. The basis for the inhibition is a structural similarity between one end of the mupirocin molecule and isoleucine. Protein synthesis is halted when the ribosome encounters the isoleucine codon through depletion of the pool of isoleucyl-tRNA. 

Mupirocin is a topical antibiotic that inhibits isoleucyl tRNA synthetase with the subsequent inhibition of protein synthesis. Mupirocin has become a mainstay in the treatment of Staph, aureus infection and colonization during hospital outbreaks, and it is in this organism that acquired resistance has arisen (Gilbart etal. 1993). 

Gilbart J., Perry CR. Slocombe B. (1993) High-level mupirocin resistance in Staphylococcus aureus evidence for two distinct isoleucyl-tRNA synthetases. Antimicrob Agents Chemother, 31, 32-38. Godfrey A.J. Bryan L.E. (1984) Intrinsic resistance and whole cell factors contributing to antibiotic resistance, hv. Antimicrobial Drug Resistance (ed. L.E. Bryan), pp. 113-145. New York Academic Press. 

Pharmacologic management of infections should cover the gram-positive organisms that most frequently cause access-related infections. Patients who have positive blood cultures should receive treatment tailored to the organism isolated. Preventive measures for access-related infections include mupirocin at the exit site and povidone-iodine ointment. The recommendations of the NKF for treatment of infections associated with hemodialysis are listed in Table 23-9. 

Intranasal S. aureus increases the risk of S. aureus exit-site infections, tunnel infections, peritonitis, and subsequent catheter loss.49 Several measures have been used to decrease the risk of peritonitis caused by S. aureus, including mupirocin cream applied daily around the exit site, intranasal mupirocin cream twice daily for 5 days each month, or rifampin 300 mg orally twice daily for 5 days, repeated every 3 months.49 Mupirocin use is preferred over rifampin to prevent the development of resistance to rifampin, although mupirocin resistance has also been reported.49 Other measures that have been used to decrease both S. aureus and P. aeruginosa infections include gentamicin cream applied twice daily and ciprofloxacin otic solution applied daily to the exit site.49... 

O Impetigo is a skin infection that most commonly afflicts young children. It is caused by group A streptococci or Staphylococcus aureus and is characterized by the development of numerous blisters that rupture and form crusts. Dicloxacillin, cephalexin, and topical mupirocin are considered the antibiotics of choice for treatment of impetigo. 

Because GAS historically has been the primary causative organism, penicillin has been the mainstay of therapy. O However, the incidence ofS. aureus impetigo is increasing, so oral penicillinase-stable penicillins or first-generation cephalosporins are now preferred.3 Erythromycin is an alternative choice when penicillin allergy is a concern. Topical mupirocin may be used alone when there are few lesions.3... 

A topical antibiotic or antifungal may be used to control the spread of infection but generally is unnecessary. For staphylococcal or streptococcal folliculitis, antibiotic ointments such as mupirocin might be administered three times daily. Antifungal shampoo can be used for dermatophytes. 

Systemic therapy with a variety of (3-lactams, macro-lides and lincosamides (clindamycin) has been the cornerstone of skin infection therapy for many years [17]. However, topical antibiotics can play an important role in both treatment and prevention of many primary cutaneous bacterial infections commonly seen in the dermatological practice [18], Indeed, while systemic antimicrobials are needed in the complicated infections of skin and skin structure, the milder forms can be successfully treated with topical therapy alone [18], The topical agents used most often in the treatment of superficial cutaneous bacterial infections are tetracyclines, mupirocin, bacitracin, polymyxin B, and neomycin. 

Topical therapy with mupirocin is equivalent to oral therapy. 

Didoxacillin 25-50 mg/kg in four divided doses Cephalexin 25-50 mg/kg in two to four divided doses Cefadroxil 30 mg/kg in two divided doses Clindamycin 10-30 mg/kg/day in three to four divided doses0 Mupirocin ointment every 8 hours0... 

MUPF resins, 75 779 Mupirocin, bacterial resistance mechanisms, 3 32t... 

Mupirocin (Bactroban) Topical antibiotic Oint 2% [15,30gm] Nasal oint 2% [1 gm] Apply to affected areas tid. Active against gram positive cocci 0.5 gm ( 4 tube) in each nostril bid x 5daysfor MRSA nasal carriers... 

Moricizine 50 Morphine 50 Morphine Sul te 50 Motrin 41 MS Contin 50 Mucomyst 12 Mupirocin 50 Myambutol 33 Mycelex 26 Mycifiadin 51 Myciguent 51 Mycobutin 60 Mycolog-ll 77 Mycostatin 53 Mylanta 47 Mysoline 57 Nabumetone 50 Nadolol 50 Nafarelin 50 Nafdl 50 Nafcillin 50 Naftifine 50 Naftin 50... 

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