[E. coli: resistance to quinolones and beta-lactams of clinical strains isolated in the Franche-Comté region of France].

Aim Of The Study: Numerous European studies have reported an increase of resistance to quinolones among E. coli. We conducted a regional study to update our knowledge on this evolution.

Materials And Methods: We evaluated the resistance phenotype and genotype of 115 clinical strains of E. coli. We collected data on individual treatment with fluoroquinolones, and the evolution of the use of these antimicrobial agents.

Results: Resistance to nalidixic acid and ciprofloxacin was 13.0 and 6.9, respectively. The frequency of resistance increased from 1999 to 2001, from 7.5% to 13.0% for nalidixic acid and from 5.4% to 6.9% for fluoroquinolones. Resistance to quinolones was significantly associated to beta-lactams resistance and was slightly higher for nosocomial isolates compared to community-acquired isolates. Previous treatment with fluoroquinolones was the major risk factor associated to E. coli resistance. From 1997 to 2001, fluoroquinolones use has increased in our hospital and particularly in the community. Analysis of molecular epidemiology shows a large clonal diversity among E. coli isolates.

Conclusion: This study confirms the evolution through resistance to quinolones of E. coli isolates. This observation is not due to dissemination of resistant clonal strains and the selective pressure exerted by fluoroquinolones influences this evolution. Therapeutic alternatives, surveillance, and restriction of fluoroquinolones use are needed to control this spread of resistance.