Fosfomycin for Uncomplicated Lower Urinary Tract Infections Caused by ESBL-Producing Klebsiella

Efficacy and Clinical Application

Fosfomycin demonstrates in vitro activity against ESBL-producing gram-negative rods, including Klebsiella species, making it potentially useful when other oral agents with in vitro activity are unavailable 1, 2
A single 3-gram oral dose of fosfomycin tromethamine can be used for uncomplicated lower UTIs caused by ESBL-producing Klebsiella, providing therapeutic urinary concentrations for 24-48 hours 3
Fosfomycin should NOT be used for pyelonephritis or complicated UTIs caused by ESBL-producing Klebsiella 3
Clinical outcomes from randomized controlled studies for ESBL-producing Klebsiella UTIs are limited, though observational studies support clinical efficacy 1, 2

Fosfomycin has a convenient single-dose or multi-dose oral regimen 1, 3
Fosfomycin has minimal propensity for collateral damage to intestinal flora 1, 2
Fosfomycin has lower bacterial efficacy compared to other first-line agents 2
Limited clinical data specifically for ESBL-producing Klebsiella UTIs 1, 2

For uncomplicated lower UTI (cystitis), a first option is Fosfomycin 3g oral powder dissolved in water as a single dose 3
For complicated UTI or pyelonephritis, Fosfomycin is NOT recommended, and carbapenems or aminoglycosides should be considered based on susceptibility testing 3, 4
If symptoms do not resolve by the end of treatment or recur within 2 weeks, perform urine culture and antimicrobial susceptibility testing 3
Common adverse effects to monitor include diarrhea, nausea, and vomiting 3

Susceptibility testing for fosfomycin is not routinely performed in many clinical laboratories, which may limit its use 1, 2