Risk factors of colonization and diversity of clinically significant carbapenemases in gut microbiota of ICU patients: a single-center prospective observational study

Background. Carbapenem-resistant Enterobacteriaceae have a major impact on ICU-stay and treatment outcomes. Objective. To identify the risk factors of colonization by CPE (carbapenemase-producing Enterobacterales) in ICU patients. Material and methods. We enrolled 94 ICU patients between November 2020 and January 2021 and divided then into 3 groups: group 1 (n=63) — all patients not colonized by CPE, group 2 (n=31) — colonized upon admission, group 3 (n=31) — colonized after 5-day ICU-stay. All patients underwent microbiological and molecular genetic testing via real-time PCR (AmpliSens MDR MBL-FL and AmpliSens MDR KPC/OXA-48-FL reagent kits) of rectal smear samples. Results. We found CPEs in rectal smear samples that mainly released carbapenemases OXA-48, NDM, KPC and their combinations. Pre-hospital risk factors for intestinal colonization by CPE were identified: male gender (OR=0.28, CI 95% [0.11, 0.74], p=0.010), hospital-stay within previous 3 months (OR=4.22, CI 95 % [1.38; 12.9], p=0.011) and previous antimicrobial therapy (OR=2.23, CI 95% [0.76; 6.54], p=0.145). There were the following risk factors after 5-day hospital-stay: primary colonization (OR=15.64, CI 95% [4.64; 52.73], p<0.0001), female gender (OR=2.51, CI 95% [0.96, 6.56], p<0.059), age (OR=0.969, CI 95% [0.931; 1.007], p=0.112), use of vasopressors (OR=27.11, CI 95% [2.43; 302.11], p=0.007), CRP (OR=0.997, CI 95% [0.992; 1.001], p=0.162), central venous catheter (OR=3.56, CI 95% [1.36; 9.30], p=0.010), proton pump inhibitors (OR 0.38, CI 95% [0.13; 1.11], p=0.077). Conclusion. Early detection of CPE and carbapenemases and their monitoring are necessary to improve the effectiveness of antimicrobial therapy in ICU patients.