Antibacterial activity in human urine of fosfomycin trometamol in an in vitro model of the urinary bladder.

The urinary concentrations of fosfomycin trometamol, norfloxacin, pipemidic acid and cotrimoxazole were studied at various times after oral administration of drugs in healthy volunteers. Using the same urine, the bactericidal activity of four antimicrobial agents against Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae in an in vitro model simulating the treatment of bacterial cystitis was also evaluated. The results obtained show that very high concentrations of the drugs were achieved in urine particularly after the oral administration of the fosfomycin trometamol. In the bladder model bactericidal activity of fosfomycin trometamol, norfloxacin and pipemidic acid were higher than that of cotrimoxazole; no resistant mutants to drugs were selected over a period of 24 h.