Impact of syndrome-specific antimicrobial stewardship interventions on use of and resistance to fluoroquinolones: An interrupted time series analysis

Background Fluoroquinolones are often prescribed unnecessarily and are an important risk factor for infection with fluoroquinolone-resistant gram-negative bacilli and Clostridioides difficile . Methods We conducted a quasi-experimental study to determine the impact of sequential syndrome-specific stewardship interventions on use of and resistance to fluoroquinolones in a tertiary care hospital. An initial 2-year intervention focused on reducing treatment of asymptomatic bacteriuria and ensuring concordance of urinary tract infection treatment with guidelines. A second 5-year intervention focused on limiting overuse of fluoroquinolones for health care–associated pneumonia in conjunction with a formal stewardship program. The primary outcomes were fluoroquinolone use and changes in use over time analyzed by segmented regression analysis. Results The asymptomatic bacteriuria and urinary tract infection intervention resulted in a significant reduction in fluoroquinolone use, with a significant change from an increasing to a decreasing rate of use (change in slope of quarterly defined daily doses/1,000 patient days –15.3, P P Pseudomonas aeruginosa , but not in Escherichia coli, Klebsiella spp., or C difficile. Conclusions Antimicrobial stewardship interventions focused on specific syndromes may be effective in reducing fluoroquinolone use. In our hospital, reduction in fluoroquinolone use resulted in increased fluoroquinolone susceptibility in P aeruginosa , but not other Enterobacteriaceae or C difficile.