Mupirocin Resistance

Shortly after the clinical use of Mupirocin began, strains of Staphylococcus aureus that were resistant to mupirocin emerged. [10] 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). Resistance in the MuL strains is probably due to mutations in the organism's wild-type isoleucinyl-tRNA synthetase. In E. coli IleRS, a single amino acid mutation was shown to alter mupirocin resistance. MuH is linked to the acquisition of a separate Ile synthetase gene, mupA. 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.
The mechanism of mupirocin differs from other clinical antibiotics, rendering cross-resistance to other antibiotics unlikely. 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. Read more:http://www.acid-lactic-bacteria.com/bulk-drug/Mupirocin/