Fosfomycin single-dose for UTI

Urinary tract infections (UTIs) are common in adult women. It has been estimated that as many as 20±30% of adult women have one or more attacks of UTI yearly. The major threat is recurrent UTIs which are usually due to reinfection with different organisms. 

The duration of treatment varies depending on the severity of the disease . Therapy for up to 14 days has been common. However in many patients infection appears to be restricted to the lower UTI.  In such patients,  single dose therapy is preferred. 

Recent studies suggest  that single dose therapy can be as effective as usual treatment. More recently, a fosfomycin salt, fosfomycin trometamol (FMT) is very effective as single dose therapy for recurrent UTI.  Fosfomycin was discovered in Spain in 1969.  It inhibits bacterial cell wall synthesis.

Many scientific studies have indicated that fosfomycin is a suitable antibiotic for lower urinary tract infection being relatively free from side effects. A high dose of Fosfomycin  drug taken is enough to prevent emergence of resistant bacteria.

 Pathogen:

The commonest pathogen being E. coli  is responsible for UTI in females (80±90% cases). Other responsible microorganisms include other Enterobacteria (Klebsiella, Pro teus, Enterobacter and Citrobacter species) and Enterococcus faecalis in a small minority of cases.

Comparative Study:

This study was carried out  to find the microbiological efficacy of fosfomycin trometamol as a first-line single dose therapy. The microbiological efficacy of a single 3 g oral dose of fosfomycin trometamol was compared with a conventional 5 day course of an oral dose of trimethoprim 200 mg twice daily.

Participants were given a single 3 g oral dose of fosfomycin trometamol, FMT and one third receiving a 5 days course of trimethoprim, TMP 200 mg  tablets twice daily. In both treatment groups (TMP and FMT), the population was homogeneous regarding age, height, weight and race.

The females in the trial were  aged between 18±65 years with uncomplicated lower urinary tract infection. The diagnosis of infection was based on symptoms (urinary burning, frequency, urgency). The symptoms had to be present for less than 48 h before entering the trial.

Females excluded from the trial were pregnant or lactating women,  patients on antibiotic therapy in the previous 2 weeks, kidney patients, hypersensitive patients, anyone unwilling to participate and any subject who was otherwise considered unfit. 

The urine samples collected before treatment were incubated for 24 h at 37°C and the amount of bacteriuria was assessed.  Patients infected with UTI were asked to provide two further samples at day 7±9 and 28±30 for follow-up and these were tested in a similar manner as mentioned earlier.

Results:

Single dose FMT 3 g  showed similar results compared to a TMP 5 day course. 

Fosfomycin, FMT has an advantage over other antibiotics used in the treatment of infection due to its unique mechanism of action. Therefore, there is a low prevalence of resistance to fosfomycin in case of UTI in females. On the contrary, Trimethoprim, TMP drug  is a common first -line treatment for uncomplicated UTIs but increasing resistance has been observed in several cases.