Microbiological profile, antimicrobial resistance, and use of antibacterial agents in septic patients with prolonged ICU stay

Introduction. Sepsis in patients with prolonged or chronic critical illness is associated with a high mortality and prolonged exposure to antimicrobial therapy. However, data on the microbiological profile and trends in antimicrobial resistance in this population remain limited.

Objective. To assess the microbiological profile, antimicrobial consumption, and dynamics of antimicrobial resistance in patients with sepsis who experienced prolonged stays in intensive care units (ICUs).

Materials and methods. We performed an analysis of the Russian Intensive Care Dataset (RICD v2.0, FNCC RR, 2017–2024). The study included patients with confirmed sepsis according to Sepsis-3 criteria who remained in the ICU for ≥24 hours. Data on microbiological testing, antimicrobial prescriptions, and resistance patterns were extracted. Antimicrobial consumption was quantified using standardized units of DDD per 100 bed-days. Integrated resistance was assessed using the Drug Resistance Index (DRI).

Results. A total of 336 patients were included (median age 64 years; male – 43.5 %, median ICU stay 44 days). The leading causative pathogens were Klebsiella pneumoniae and Pseudomonas aeruginosa. Between 2022 and 2024, consumption of aminoglycosides, cephalosporins, cotrimoxazole, linezolid, and tigecycline increased, while use of carbapenems, levofloxacin, and metronidazole declined. Resistance to ceftazidime-avibactam rose from 37 % to 87 % (p=0.004), whereas resistance rates decreased for tigecycline, vancomycin, and gentamicin (p<0.01). The overall DRI reached 32.6 % in 2022, 41.2 % in 2023, and 34.1 % in 2024.

Conclusions. This study demonstrates persistently high levels of antimicrobial resistance among septic patients with prolonged ICU stays, with a predominance of Gram-negative pathogens in the etiological structure of infections. Every third empirical prescription of antibiotic therapy was accompanied by resistance of the infectious agent. These findings highlight the need for continuous microbiological surveillance, optimization of antimicrobial stewardship programs.

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