In vitro susceptibility testing procedures for fosfomycin tromethamine.

Fosfomycin tromethamine (previously fosfomycin trometamol) is an orally administered fosfomycin which may be used for single-dose therapy of uncomplicated urinary tract infections. Fosfomycin tromethamine, norfloxacin, and trimethoprim-sulfamethoxazole inhibited greater than 90% of 352 bacterial isolates representing 25 different species; trimethoprim and nalidixic acid had narrower spectrums of activity. Strains of Escherichia, Citrobacter, Enterobacter, and Klebsiella species were much more susceptible when glucose-6-phosphate was added to the test medium, but isolates belonging to other genera were not affected.