P399 - THE GUT AS A RESERVOIR: CRB COLONIZATION AND ITS IMPACT ON CLINICAL OUTCOMES IN THE ICU

P399

THE GUT AS A RESERVOIR: CRB COLONIZATION AND ITS IMPACT ON CLINICAL OUTCOMES IN THE ICU

I. Patsis¹, P. Koufopoulos², S. Manioudaki¹, C. Koufopoulou^3,*, I. Bader¹, Z. Athanassa¹, E. Mylona⁴, M. Masouridi⁵, A. Kessaris¹, A. Sakagianni¹

¹Intensive Care Unit, ²Internal Medicine, Sismanogleio General Hospital of Athens, Marousi, ³Anesthesiology Department, Aretaieion Hospital National and Kapodistrian University of Athens, Athens, ⁴Biopathology Department, ⁵Infection Control Department, Sismanogleio General Hospital of Athens, Marousi, Greece

Rationale: The gut microbiome plays a pivotal role in immune regulation, metabolic homeostasis, and clinical outcomes in critically ill patients. Colonization of the gastrointestinal tract by carbapenem-resistant bacteria (CRB) represents a major global health threat, particularly in intensive care units (ICUs), where invasive procedures, antibiotic overuse, and compromised host defenses create an ideal environment for resistant pathogens.

Methods: A retrospective observational study was conducted in the ICU of a tertiary care hospital during one year. Rectal swab screening for CRB colonization was performed at initial ICU admission for 224 patients. Positive swabs were cultured on Brilliance CRE agar, and carbapenem resistance was confirmed via susceptibility testing and phenotypic detection of carbapenemase production. Statistical analysis included Pearson chi-square, Wilcoxon-Mann-Whitney, and Fisher’s exact tests.

Results: Out of 224 ICU patients screened, 45 (20.1%) were positive for CRB gut colonization. The most commonly identified organisms were Klebsiella pneumoniae (40.0%), Acinetobacter baumannii (20.0%), and Pseudomonas aeruginosa (8.9%). Colonized patients had significantly longer ICU stays (median 14 vs. 7 days, p=0.036), longer total hospital stays (median 25 vs. 17 days, p=0.033), and higher all-cause mortality (55.0% vs. 31.7%, p=0.006). Though CRB bacteremia was nearly doubled among colonized patients (17.8% vs. 8.9%), it was not statistically significant (p=0.105). COVID-19 status did not significantly influence outcomes (Table 1).*p-value≤0.05, ±median (IQR)

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Conclusion: Gut colonization with CRB in ICU patients is independently associated with adverse clinical outcomes, potentially serving as a source of secondary infections through translocation or invasive procedures.

References:         1. Szychowiak, P., et al. The role of the microbiota in the management of intensive care patients. Ann. Intensive Care 12, 3 (2022).

Disclosure of Interest: None declared