To evaluate changes in outpatient fluoroquinolone (FQ) and nitrofurantoin (NFT) use and resistance among E. coli isolates after a change in institutional guidance to use NFT over FQs for acute uncomplicated cystitis.

Retrospective preintervention–postintervention study.

Urban, integrated healthcare system.

Adult outpatients treated for acute cystitis.

We compared 2 time periods: January 2003–June 2007 when FQs were recommended as first-line therapy, and July 2007–December 2012, when NFT was recommended. The main outcomes were changes in FQ and NFT use and FQ- and NFT-resistant E. coli by time-series analysis.

Overall, 5,714 adults treated for acute cystitis and 11,367 outpatient E. coli isolates were included in the analysis. After the change in prescribing guidance, there was an immediate 26% (95% CI, 20%–32%) decrease in FQ use (P<.001), and a nonsignificant 6% (95% CI, −2% to 15%) increase in NFT use (P=.12); these changes were sustained over the postintervention period. Oral cephalosporin use also increased during the postintervention period. There was a significant decrease in FQ-resistant E. coli of −0.4% per quarter (95% CI, −0.6% to −0.1%; P=.004) between the pre- and postintervention periods; however, a change in the trend of NFT-resistant E. coli was not observed.

In an integrated healthcare system, a change in institutional guidance for acute uncomplicated cystitis was associated with a reduction in FQ use, which may have contributed to a stabilization in FQ-resistant E. coli. Increased nitrofurantoin use was not associated with a change in NFT resistance.

Infect Control Hosp Epidemiol 2017;38:461–468

To evaluate the long-term outcomes of an antimicrobial stewardship program (ASP) implemented in a hospital with low baseline antibiotic use.

Quasi-experimental, interrupted time-series study.

Public safety net hospital with 525 beds.

Implementation of a formal ASP in July 2008.

We conducted a time-series analysis to evaluate the impact of the ASP over a 6.25-year period (July 1, 2008–September 30, 2014) while controlling for trends during a 3-year preintervention period (July 1, 2005–June 30, 2008). The primary outcome measures were total antibacterial and antipseudomonal use in days of therapy (DOT) per 1,000 patient-days (PD). Secondary outcomes included antimicrobial costs and resistance, hospital-onset Clostridium difficile infection, and other patient-centered measures.

During the preintervention period, total antibacterial and antipseudomonal use were declining (−9.2 and −5.5 DOT/1,000 PD per quarter, respectively). During the stewardship period, both continued to decline, although at lower rates (−3.7 and −2.2 DOT/1,000 PD, respectively), resulting in a slope change of 5.5 DOT/1,000 PD per quarter for total antibacterial use (P=.10) and 3.3 DOT/1,000 PD per quarter for antipseudomonal use (P=.01). Antibiotic expenditures declined markedly during the stewardship period (−$295.42/1,000 PD per quarter, P=.002). There were variable changes in antimicrobial resistance and few apparent changes in C. difficile infection and other patient-centered outcomes.

In a hospital with low baseline antibiotic use, implementation of an ASP was associated with sustained reductions in total antibacterial and antipseudomonal use and declining antibiotic expenditures. Common ASP outcome measures have limitations.

Infect Control Hosp Epidemiol 2015;00(0): 1–9