Antimicrobial stewardship programs (ASPs) aim to mitigate antimicrobial resistance (AMR) by optimizing antibiotic use including reducing unnecessary broad-spectrum therapy. This study evaluates the impact of ASP funding and resources on the use of broad-spectrum antibiotics in Ontario hospitals.

We conducted a cross-sectional study of antimicrobial use (AMU) across 63 Ontario hospitals from April 2020 to March 2023. The Ontario ASP Landscape Survey provided data on ASP resourcing and antibiotic utilization. The main outcome was the proportion of all antibiotics that were broad-spectrum, defined as: fluoroquinolones; third-generation cephalosporins; beta-lactam/beta-lactamase inhibitors; carbapenems; clindamycin; and parenteral vancomycin. Secondary outcomes included the proportions of individual antibiotic classes listed above and anti-pseudomonal agents. Statistical analysis involved logistic regression to determine the odds ratio (OR) of the association between ASP funding/resourcing and broad-spectrum antibiotic use.

Among 63 hospitals, 48 reported designated ASP funding/resources. Median broad-spectrum antibiotic use was 52.5%. ASP funding/resources was not associated with overall broad-spectrum antibiotic use (0.97, 95% CI: 0.75–1.25, P = 0.79). However, funding was associated with lower use of fluoroquinolones (OR 0.67, 95% CI: 0.46–0.96, P = 0.03), clindamycin (OR 0.69, 95% CI: 0.47–1.00, P = 0.05), and anti-pseudomonal agents (OR 0.76, 95% CI: 0.59–0.98, P = 0.03).

The presence of designated funding and resources for hospital ASPs is linked to reduced use of specific broad-spectrum antibiotics but not overall broad-spectrum antibiotic use. Enhancing ASP resourcing may be an important factor in limiting targeted antibiotic use, thereby increasing the effectiveness of efforts to mitigate AMR.

To evaluate temporal trends in the prevalence of gram-negative bacteria (GNB) with difficult-to-treat resistance (DTR) in the southeastern United States. Secondary objective was to examine the use of novel β-lactams for GNB with DTR by both antimicrobial use (AU) and a novel metric of adjusted AU by microbiological burden (am-AU).

Retrospective, multicenter, cohort.

Ten hospitals in the southeastern United States.

GNB with DTR including Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter spp. from 2015 to 2020 were tracked at each institution. Cumulative AU of novel β-lactams including ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilastatin/relebactam, and cefiderocol in days of therapy (DOT) per 1,000 patient-days was calculated. Linear regression was utilized to examine temporal trends in the prevalence of GNB with DTR and cumulative AU of novel β-lactams.

The overall prevalence of GNB with DTR was 0.85% (1,223/143,638) with numerical increase from 0.77% to 1.00% between 2015 and 2020 (P = .06). There was a statistically significant increase in DTR Enterobacterales (0.11% to 0.28%, P = .023) and DTR Acinetobacter spp. (4.2% to 18.8%, P = .002). Cumulative AU of novel β-lactams was 1.91 ± 1.95 DOT per 1,000 patient-days. When comparing cumulative mean AU and am-AU, there was an increase from 1.91 to 2.36 DOT/1,000 patient-days, with more than half of the hospitals shifting in ranking after adjustment for microbiological burden.

The overall prevalence of GNB with DTR and the use of novel β-lactams remain low. However, the uptrend in the use of novel β-lactams after adjusting for microbiological burden suggests a higher utilization relative to the prevalence of GNB with DTR.