In vitro susceptibility testing procedures for fosfomycin tromethamine

Area of Science:

• Pharmacology
• Microbiology
• Infectious Diseases

Background:

• Fosfomycin tromethamine is an oral antibiotic.
• It is utilized for single-dose treatment of uncomplicated urinary tract infections (UTIs).

Purpose of the Study:

• To evaluate the in vitro antimicrobial activity of fosfomycin tromethamine.
• To compare its spectrum of activity against other common antibiotics used for UTIs.

Main Methods:

• Antimicrobial susceptibility testing was performed on 352 bacterial isolates from 25 species.
• Inhibition percentages were determined for fosfomycin tromethamine, norfloxacin, trimethoprim-sulfamethoxazole, trimethoprim, and nalidixic acid.
• The effect of glucose-6-phosphate on susceptibility was assessed for specific bacterial genera.

Main Results:

• Fosfomycin tromethamine, norfloxacin, and trimethoprim-sulfamethoxazole demonstrated broad-spectrum activity, inhibiting over 90% of isolates.
• Trimethoprim and nalidixic acid exhibited narrower spectra of activity.
• Susceptibility of Escherichia, Citrobacter, Enterobacter, and Klebsiella species increased significantly with the addition of glucose-6-phosphate.

Conclusions:

• Fosfomycin tromethamine exhibits significant in vitro activity against a wide range of bacteria relevant to UTIs.
• The addition of glucose-6-phosphate enhances the efficacy of fosfomycin against certain Gram-negative bacteria.
• Fosfomycin tromethamine is a viable option for single-dose UTI therapy.