Selective antibiotic susceptibility reporting and broad-spectrum intravenous antibiotic use: A multicentre ecological study

Recent estimates of inpatient antibiotic use in the USA suggest that broad-spectrum antibiotic use has increased significantly. The objective of this study was to assess the impact of a selective antibiotic susceptibility reporting intervention on broad-spectrum intravenous (i.v.) antibiotic use in seven hospitals of a health system in New Jersey. This was a retrospective pre- and post-intervention ecological study. Standardised selective antibiotic susceptibility reporting rules were developed and implemented between January 2016 and June 2017. The 8 months before and after each individual hospital's implementation constituted the pre- and post-intervention study periods. The primary outcome was the rate of broad-spectrum i.v. antibiotic use for hospital-onset/multidrug-resistant infections (broad MDR). Secondary outcome measures were the use rates of non-glycopeptide anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) agents, carbapenems, non-carbapenem antipseudomonal β-lactams, third-generation cephalosporins, first/second-generation cephalosporins, fluoroquinolones and narrow-spectrum penicillins. Antibiotic use data were collected as inpatient i.v. antibiotic days of therapy per 1000 patient days (DOT/1000-PD). Interrupted time series analysis with segmented regression was used to compare outcomes. There was no significant change in the use of broad MDR agents (slope change, +0.54 DOT/1000-PD per month, 95% confidence interval –1.78 to 2.87) or other antibiotic classes. Whilst the implementation of selective antibiotic susceptibility reporting across seven hospitals had no impact on overall broad-spectrum i.v. antibiotic use, further study is needed to determine the long-term impact of this intervention.