Association between fluoroquinolone utilization rates and susceptibilities of gram-negative bacilli: Results from an 8-year intervention by an antibiotic stewardship program in an inner-city United States hospital

This study evaluated an antibiotic stewardship program (ASP) intervention aimed at reducing inpatient fluoroquinolone (FQ) use and examined its impact on ciprofloxacin susceptibilities of gram-negative bacteria in a large 611-bed community hospital. A two-step ASP intervention was implemented: an electronic medical record algorithm that prompted physicians to re-evaluate FQ use shortly after admission and changed institutional UTI/pneumonia guidelines that recommended options alternate to FQs for first-line empiric antibiotic therapy in 2010 and 2011 respectively. Between 2007 and 2017 FQ use and ciprofloxacin susceptibilities of all non-duplicate cultured isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa obtained ≥72 h after admission were reviewed. Ambulatory care isolates served as a comparison group. FQ utilization rates and relationships to ciprofloxacin susceptibility were evaluated using interrupted time series models. Over the 11-year period, FQ use decreased from 110.0 (2007) to 26.2 (2017) days of therapy/1000 days at risk (p