Temporal Trends in Antimicrobial Resistance Among Clinically Important Pathogens in Iraq, 2021-2024: Implications for Empirical Antimicrobial Therapy

To characterise temporal changes in antimicrobial resistance (AMR) among clinically important bacterial pathogens in Iraq during 2021-2024 and examine their implications for empirical antimicrobial therapy and stewardship. We conducted a retrospective longitudinal analysis of aggregated national AMR surveillance data for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Annual resistance proportions were evaluated across clinically relevant antimicrobials. Temporal change was characterised using absolute percentage-point changes and exploratory linear regression. Resistance trajectories were interpreted in relation to empirical treatment options and antimicrobial stewardship. The analysis included 92,338 organism records: 40,496 (43.9%) E. coli, 24,621 (26.7%) S. aureus, 18,223 (19.7%) K. pneumoniae and 8,998 (9.7%) P. aeruginosa. In 2024, ceftriaxone resistance reached 82.9% in E. coli and 65.2% in K. pneumoniae, while ciprofloxacin resistance was 55.4% and 57.9%, respectively. Meropenem resistance reached 37.4% in K. pneumoniae and 62.3% in P. aeruginosa. Conversely, resistance declined for amoxicillin-clavulanate in E. coli (83.5% in 2021 to 57.2% in 2024) and piperacillin-tazobactam in P. aeruginosa (46.4% to 32.9%). Several pathogen-antimicrobial combinations showed marked year-to-year variation, and no temporal trend remained statistically significant after false discovery rate correction. Resistance to several agents central to empirical therapy remains high in Iraq, while substantial carbapenem resistance constrains reliance on carbapenem escalation when resistance to other {beta}-lactams is suspected. Heterogeneous trajectories indicate that empirical recommendations should not rely on single-year national antibiograms alone and support regular integration of national and local resistance surveillance into empirical treatment and antimicrobial stewardship strategies.