In VitroActivity of Fosfomycin Trometamol Against Pathogens from Urinary Tract Infections: A Spanish Multicenter Study

Abstract

The in-vitro susceptibilities of a total of 1371 urinary tract pathogens to fosfomycin trometamol were determined. According to the NCCLS breakpoints, Enterobacteriaceae and gram-positive microorganisms were, in general, very sensitive to this antimicrobial. More than 90.0% of the Escherichia coli and Citrobacter spp. and more than 70.0% of the Klebsiella pneumoniae, K. oxytoca, Enterobacter spp., Proteus mirabilis, Staphylococcus aureus, coagulase-negative staphylococci and Enterococcus spp. strains tested were susceptible to fosfomycin trometamol. However, Pseudomonas aeruginosa and Acinetobacter spp. strains were more resistant. In general, recent clinical isolates from urinary tract infections (UTIs) in both community and hospital were also very sensitive (> 80.0%) to fosfomycin, its activity being higher than that of the rest of the antimicrobials commonly used for therapy of uncomplicated UTIs. More than 75.0% of the most frequently isolated pathogens from UTIs, except for P. aeruginosa (31.8%) and Acinetobacter spp. (11.1%), were susceptible to fosfomycin trometamol. The results obtained in this study, together with the infrequency of side effects and its pharmacokinetic properties, indicate that fosfomycin trometamol may be a useful alternative for single-dose therapy of uncomplicated UTIs.

Clinico-Microbiological Investigation on Fosfomycin and Tigecycline Resistant Gram-Negative Bacilli Isolated from Urinary Tract Infections: A Potential Resurgence

“…A study performed in Spain, which its results are similar to the current study, reported that > 90% E. coli and Citrobacter and > 70% of K. pneumoniae, Enterobacter spp., Proteus mirabilis, S. aureus, Coagulase-negative staphylococci, and Enterococcus spp. isolated from the urine were susceptible to fosfomycin (37,38). Korean and UK studies provided similar results with 87.7%, and 95.1% of E. coli and K. pneumonia, respectively, were susceptible to fosfomycin (39).…”

Pharmacological properties of oral antibiotics for the treatment of uncomplicated urinary tract infections

“…60 It has a relatively broad spectrum of activity and, notwithstanding the possible mechanisms of bacterial resistance, has maintained good activity against the main bacterial species responsible for UTIs. [60][61][62][63] Many different factors may play a role in this preserved activity. These include the use of a single dose for the treatment of uncomplicated UTIs and two consecutive doses for prophylaxis of urological procedures, the rapid concentration-dependent killing activity with reduced effect on selecting resistant mutants (and when present, these strains have reduced fitness due to the high biological cost of the genetic modification) and the limited use in veterinary medicine.…”

“…prostate, lungs, inflamed tissues, bone, cerebrospinal fluid, abscess fluid and heart valves. 62 For example, at 3 and 12 h after an oral 3 g dose, prostatic fosfomycin concentrations are 25 and 7 mg/L, respectively. 68,69 Fosfomycin is excreted unchanged in the urine via glomerular filtration.…”

Pharmacokinetic and pharmacodynamic aspects of antimicrobial agents for the treatment of uncomplicated urinary tract infections

“…It is bactericidal owing to the inhibition of a cytoplasmic enzyme (pyruvyltransferase) that is active during the first step of bacterial cell wall (peptoglycan) synthesis [30]. Notwithstanding the possible mechanisms of bacterial resistance, this antibiotic has maintained good activity against the main bacterial species responsible for urinary infection [31,32]. After oral administration of 3 g of the tromethamine salt of fosfomycin, high urinary concentrations (1000-4000 mg/L) are achieved and remain at 100 mg/L for at least 30-40 h, guaranteeing good efficacy in the treatment of uncomplicated UTI even after a single administration [33,34] (Table 3).…”