Ciprofloxacin for selective decontamination of the alimentary tract in patients with acute leukemia during remission induction treatment: the effect on fecal flora.

Ciprofloxacin, a new quinolone derivative, was given prophylactically (500 mg twice a day) to 15 patients with acute leukemia during remission induction treatment for a mean duration of 42 days. The effect on the microbial flora of the alimentary tract was evaluated. A rapid elimination of Enterobacteriaceae within three to five days was observed. Bacteroides and Clostridium species were not affected, but the number of anerobic nonsporeforming gram-positive bacilli and anaerobic cocci was decreased. Nine ciprofloxacin-resistant gram-negative rods (Pseudomonas and Acinetobacter species) were isolated but without colonization or subsequent infection. Four of the five bacteriologically documented infections in these patients were caused by gram-positive cocci. Ciprofloxacin was well tolerated, and no side effects were noticed.