Threshold modeling for antibiotic stewardship in Oman.

Area of Science:

• Infectious Diseases
• Clinical Pharmacy
• Epidemiology

Background:

• Antimicrobial stewardship is crucial for rational antibiotic use.
• Balancing antibiotic access with resistance control presents challenges.
• This research focused on carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Klebsiella pneumoniae, and extended-spectrum β-lactamases-producing Escherichia coli.

Purpose of the Study:

• To identify antibiotic usage targets associated with the incidence of specific resistant gram-negative pathogens.
• To establish critical incidence rate cutoffs for these pathogens.
• To determine antibiotic use thresholds that correlate with increased pathogen incidence.

Main Methods:

• Ecological population-level design using retrospective data.
• Monthly pathogen cases and antibiotic use data collected from January 2015 to December 2023.
• Nonlinear modeling and logistic regression applied to identify thresholds.

Main Results:

• Critical incidence rates established: 0.199 cases/100 occupied bed-days (OBD) for carbapenem-resistant A. baumannii, 0.175 for carbapenem-resistant K. pneumoniae, and 0.146 for ESBL-producing E. coli.
• Identified antibiotic use thresholds (defined daily dose/100 OBD): aminoglycosides (0.59), carbapenems (6.31), piperacillin-tazobactam (3.71), third-generation cephalosporins (3.71), and fluoroquinolones (1.91).
• Exceeding these antibiotic use thresholds was associated with accelerated incidence rates of these gram-negative pathogens.

Conclusions:

• Threshold logistic models are effective tools for antimicrobial stewardship.
• These models can inform interventions to manage antimicrobial resistance in hospitals.
• Implementing these thresholds can help control the spread of resistant gram-negative infections.