Paper Information

Antimicrobial resistance (AMR) is a major threat in intensive care units (ICUs). Evidence on determinants of multidrug-resistant (MDR) infections in ICUs remains limited. We aimed to assess temporal, institutional, and antibiotic-use drivers of MDR incidence across 59 Chilean ICUs across 40 hospitals (2015-2024).

Between 2015 and 2024, MDR incidence declined by 21% (1.82-1.44 per 1000 patient-days), driven by reductions in CRPA (4.8-1.9), MRSA (3.2-1.0), and VRE (1.4-0.9). CRE declined modestly (2.7-1.7), while CPE increased from 0 to 1.3 after 2017. Adult ICUs and public hospitals had higher IDRs than paediatric and private units. In adjusted models, quinolone use was associated with higher MDR incidence (β = 0.08, 95% CI 0.03-0.14; p = 0.004), as was carbapenem use (β = 0.06, 0.03-0.09; p < 0.0001). Each additional hour of infectious disease specialist coverage per 100 bed-days reduced MDR incidence by ∼2% (β = -0.02, -0.03 to -0.01; p = 0.023). MRSA increased with quinolones, while CRE and CRPA increased with carbapenems.

We conducted an ecological time-trend analysis using data from the Collaborative Group on Bacterial Resistance. MDR incidence density rates (IDRs) in 1000 patient-days comprised methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli, carbapenem-resistant Enterobacterales (CRE), Pseudomonas aeruginosa (CRPA), Acinetobacter baumannii (CRAB), and carbapenemase-producing Enterobacterales (CPE). IDRs were modelled using three-level Bayesian hierarchical regressions, accounting for repeated annual measures within hospital-pathogen pairs and differences between hospitals. Models included hospital infrastructure, infectious disease specialist hours, antimicrobial stewardship (AMS) programmes, socioeconomic variables, and antibiotic use (cephalosporins, quinolones, carbapenems; in DDDs/1000 bed-days).

No funding.

MDR incidence in Chilean ICUs remains high and driven by quinolone and carbapenem use. Strengthening AMS and specialist oversight, alongside stricter prescribing, could reduce burdens.