Objectives: High rates of methicillin-resistant Staphylococcus aureus (MRSA) and fluoroquinolone-resistant Pseudomonas aeruginosa may be related, in part, to the overuse of fluoroquinolones. The objective was to analyse and correlate long-term surveillance data on MRSA and fluoroquinolone-resistant P. aeruginosa rates and antibiotic consumption after implementation of an institution-wide programme to reduce fluoroquinolone use.
Methods: An interrupted time series/quasi-experimental study of monthly fluoroquinolone use and MRSA and fluoroquinolone-resistant P. aeruginosa isolation rates was carried out in a tertiary hospital during three periods: pre-intervention (January 2000 – August 2005), intervention (September 2005 – March 2006), and post-intervention (March 2006–March 2010). The effect of the intervention on the consumption of fluoroqui- nolones and bacterial resistance was assessed using segmented regression analyses.
Results: Mean monthly fluoroquinolone consumption dropped by 29.1 defined daily doses per 1000 patient- days (DDD/1000 PD) (95% CI 13.1–45.9; P1⁄40.0005) from a mean of 148.2 to 119.1 DDD/1000 PD during the intervention period. A sustained and significant decrease in fluoroquinolone consumption of 20.95 DDD/ 1000 PD/month was also observed during the post-intervention period (P1⁄40.0002). During the post- intervention period the rate of fluoroquinolone-resistant P. aeruginosa continuously decreased, from a mean of 42% to 26%, with a constant relative change rate of 213%/year (95% CI 219 to 25, P1⁄40.001). A decrease in the MRSA rate was observed during the intervention period, from a mean resistance rate of 27% to 21% (P , 0.0001).
Conclusions: We showed the sustained impact of a fluoroquinolone control programme on the reduction of fluoroquinolone use with a significant decrease in fluoroquinolone-resistant P. aeruginosa and MRSA rates over 4 years.

• Quantitative data - Quantitative data were used during the intervention

• Human - All activities regarding organisations and individuals involved in health products and services

• Healthcare delivery