Fosfomycin – “new old” antibiotic with a wide spectrum of action but tricky characteristics concerning in vitro effectiveness testing
Abstract
Fosfomycin inhibits bacterial cell wall synthesis through a unique mechanism of action at a step prior to that inhibited by β‑lactams. It inhibits MurA, which initiates peptidoglycan biosynthesis of the bacterial cell wall of gram‑positive and gram‑negative bacteria.
Inherent resistance to fosfomycin is mainly through MurA mutations. Acquired resistance involves modifications of membrane transporters that prevent fosfomycin from entering the bacterial cell, acquisition of plasmid‑encoded genes that inactivate fosfomycin, and MurA mutations.
Agar dilution method gold standard method for susceptibility testing fosfomycin in vitro. Fosfomycin is an antibiotic with bactericidal activity, good tolerance, good tissue penetration, absence of induction of multidrug‑resistant microorganisms and activity against multidrug‑resistant gram‑positive and gram‑negative bacteria.