Effects of oral ciprofloxacin on aerobic gram-negative fecal flora in patients with cirrhosis: results of short- and long-term administration, with daily and weekly dosages

Background/Aims: Selective intestinal decontamination has been proposed to prevent spontaneous bacterial peritonitis in cirrhosis. Because of the cost of antibiotics and the development of resistant bacteria, we have evaluated the effect of different schemes and doses of oral ciprofloxacin on aerobic gram-negative fecal flora in cirrhotic patients. Method: Twenty-nine cirrhotic patients were allocated to four groups to receive: Group 1: 500 mg/day for 2 weeks (six patients); Group 2: 1000 mg twice a week for 2 weeks (six patients); Group 3: 1000 mg once a week for 2 weeks (six patients); and Group 4: 1000 mg once a week for 12 weeks (11 patients). Quantitative analysis of the gram-negative fecal flora was performed before and 1 and 2 weeks after initiation of treatment in patients in groups 1, 2 and 3 and before and 4, 8 and 12 weeks after initiation of treatment in patients in Group 4. Results: Complete eradication of gram-negative bacilli was observed in four of six patients in Group 1. In contrast, only one patient eradicated gram-negative bacilli in Group 2 and Group 3. In long-term administration of ciprofloxacin (Group 4), only two of 11 patients had persistent eradication of gram-negative bacilli. Four patients developed E. coli resistant to ciprofloxacin (one of them associated to resistant Klebsiella). No patient developed bacterial infection during the study period. Conclusion: Oral ciprofloxacin administered in a weekly dose is ineffective in selective intestinal decontamination. Different mechanisms, including the emergency of ciprofloxacin-resistant organisms, could account for this failure. Therefore, our results suggest that weekly administration of ciprofloxacin is not useful in preventing spontaneous bacterial peritonitis.