Influence of a prophylactic single dose of ciprofloxacin on the level of resistance of Escherichia coli to fluoroquinolones in urology

During the years 1991-1996 an increase in fluoroquinolone-resistant Escheri chia coil was observed at the Urological Department of the Municipal Hospit al in Straubing, Germany. A prospective study was undertaken to investigate the influence of single-dose prophylaxis (SDP) using 500 mg ciprofloxacin orally on the level of resistance to ciprofloxacin of faecal E. coli. One h undred and five patients were recruited to the study: E. coil resistance to ciprofloxacin before prophylaxis was 3% (3/91) in contrast to 12% (5/42) a fter prophylaxis (P = 0.052). In 31 isolates no major change in the low MIC values before and after SDP was observed. PFGE showed clonal diversity in about half of the cases. Three isolates showed low-level resistance and thr ee isolates high-level resistance to ciprofloxacin both before and after SD P. PFGE showed clonal identity in all cases. All patients had previously be en treated with fluoroquinolones (FQ). In two isolates emergence of high-le vel resistance to ciprofloxacin after SDP occurred. PFGE showed clonal dive rsity in both cases. We conclude that after SDP with 500 mg ciprofloxacin t here is a shift to Gram-positive bacteria in the faeces and an increase in the rate of FQ resistance. Since selection of highly resistant E. coli is p ossible, a careful risk-benefit evaluation of prophylaxis with FQ is indica ted. (C) 2000 Elsevier Science B.V. and International Society of Chemothera py. All rights reserved.