Gut decontamination by oral ofloxacin and ciprofloxacin in healthy volunteers.

The selectivity of enterobacterial decontamination during oral ofloxacin and ciprofloxacin was studied in 15 volunteers. Dilution studies of 294 faecal samples were made to monitor concentrations of enterobacteria, yeasts and enterococci. Detection of beta-aspartylglycine content was used for evaluation of interaction with the indigenous (mostly anaerobic) flora. Inactivation of ofloxacin and ciprofloxacin by faeces was studied to explain the effects of gut decontamination. Escherichia coli was successfully eliminated from the gut in all volunteers during treatment. Decontamination was found to be more or less selective with both quinolones, although yeast overgrowth and decrease of enterococci was significantly higher with ciprofloxacin. This may be explained by the higher intrinsic activity of ciprofloxacin against anaerobic flora, the inactivation by faeces being low for both agents. Ofloxacin and ciprofloxacin are two new quinolones of value in the therapy of infections between 'waist and knee' (e.g. cystitis, enteritis, prostatitis) because of the elimination of the infection focus combined with the eradication of the source.