Fosfomycin (Molecule of the Month for April 2010)
Fosfomycin (also known as phosphomycin and phosphonomycin) is a broad-spectrum antibiotic produced by certain Streptomyces species. Fosfomycin is indicated in the treatment of urinary tract infections, where it is usually administered as a single oral megadose. The drug is well tolerated and has a low incidence of harmful side-effects. However, development of bacterial resistance under therapy is a frequent occurrence and makes fosfomycin unsuitable for sustained therapy of severe infections. Additional uses have been proposed. The global problem of advancing antimicrobial resistance has led to a renewed interest in its use more recently.
Fosfomycin inhibits bacterial cell wall biogenesis by inactivating the enzyme UDP-N-actetylglucosamine-3-enolpyruvyltransferase, also known as MurA. This enzyme catalyzes the committed step in peptidoglycan biosynthesis, namely the ligation of phosphoenolpyruvate (PEP) to the 3'-hydroxyl group of UDP-N-acetylglucosamine. This pyruvate moiety provides the linker that bridges the glycan and peptide portion of peptidoglycan. Fosfomycin is a PEP analog that inhibits MurA by alkylating an active site cysteine residue (Cys 115 in the Escherichia coli enzyme).
Mutations that inactivate the non-essential glycerophosphate transporter render bacteria resistant to fosfomycin.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for April 2010 )