Incidence and clinical impact of fluoroquinolone-resistant Escherichia coli in the faecal flora of cancer patients treated with high dose chemotherapy and ciprofloxacin prophylaxis.

This study evaluated the susceptibility of Escherichia coli to quinolones in 72 stool samples collected from 31 patients with solid tumours who had undergone high dose chemotherapy (HDC) and peripheral blood stem-cell (PBSC) rescue with ciprofloxacin prophylaxis. Samples were obtained at admission, after completing prophylaxis and three months later. All E. coli strains isolated from baseline samples were susceptible to quinolones. Fluoroquinolone-resistant E. coli strains were isolated in 10 (32%) patients in the second sample. In eight of these patients isolates were susceptible 3 months later. No patient developed infection due to fluorquinolone-resistant E. coli. No differences were observed in outcome between patients with susceptible and resistant flora.