Active substances: Norfloxacin
Randomized studies have also shown a combination of intravenous fosfomycin and metronidazole to be effective for the prophylaxis of infection during elective and emergent abdominal surgery.
Because of lack of availability of a parenteral form of fosfomycin in the United States, this review has concentrated on its role in this country as a potentially useful oral antimicrobial agent. Bacterial resistance to fosfomycin is usually chromosomally mediated.
Of 60 isolates tested in Italy, only five carried plasmids encoding fosfomycin resistance. Chromosomally mediated resistance occurs essentially because of mutations that interfere with these two transport mechanisms, resulting in reduced intracellular concentrations of the drug in the target bacteria.
Since the first report of plasmid-mediated resistance to fosfomycin in S.
One of these plasmid-harbored genes has been characterized and is called the fosA gene. The protein encoded by the fosA gene brings about glutathione conjugation of fosfomycin, rendering it ineffective.
The fosA gene has not been found in grampositive bacteria. Some S.
The mechanism of resistance conferred by the fosB gene has not been determined. Fosfomycin acts at a target site that is not affected by other antimicrobials.
As a result, there seems to be little cross-resistance between fosfomycin and the other commonly used urinary antibiotics. Concerns have been expressed about the potential for development of resistant mutants if fosfomycin is used for prolonged periods of time to treat difficult infections.
A survey conducted in the early 1990 s of 7453 urinary pathogens in three hospitals in Italy showed that the prevalence of resistance to fosfomycin was only approximately 2. The cost of a sachet of fosfomycin is U.
The medication cost of treating one episode of uncomplicated UTI with this drug is approximately U. Conclusions The efficacy of single-dose fosfomycin in the treatment of uncomplicated UTIs in women has been well established in clinical studies and extensive clinical application in several countries in Europe and in Japan.
So far, such use has not led to the development of resistance. There are no compliance issues with fosfomycin because it involves a single dose.
The cost of treating one episode of cystitis compares favorably with most treatments currently available.
Distinguishing between infection and colonization is important to avoid the indiscriminate use of fosfomycin in asymptomatic bacteriuria in the elderly and in patients with chronic indwelling urinary catheters. In recurrent UTIs that are not caused by a surgically correctable abnormality, prudent use of fosfomycin could decrease development of resistance by decreasing antibiotic selection pressure.