Gut barrier dysfunction and multidrug-resistant bacterial translocation in adult critical illness: Mechanistic insights from a systematic review

Table 1 Characteristics of included clinical studies evaluating gut barrier dysfunction and multidrug-resistant bacterial translocation in critically ill adults

Ref.	Country	Study design	ICU population	Organism/focus	Key findings
Thom et al[22], 2010	United States	Observational cohort	ICU patients	Acinetobacter baumannii	Identical strains detected in GI colonization and bloodstream infection
Jung et al[20], 2010	South Korea	Cohort	ICU patients	MDR Acinetobacter baumannii	Colonization associated with increased risk of bacteraemia
Giannella et al[17], 2014	Italy	Prospective multicentre cohort	Rectal carriers	CRKP	Rectal colonization strongly predicted subsequent bacteraemia
Giacobbe et al[19], 2017	Italy	Multicentre retrospective cohort	Colonized patients	CRKP	Prior infections predicted CRKP bacteraemia
Freedberg et al[11], 2018	United States	Prospective observational study	ICU patients	Gastrointestinal microbiome colonization	GI pathogen colonization at ICU admission associated with subsequent infection and mortality
Amberpet et al[21], 2018	India	Prospective study	Pediatric ICU patients	Vancomycin-resistant enterococci	Intestinal colonization identified as a major risk factor for MDR transmission
Zaborin et al[12], 2014	United States	Microbiome observational study	Critically ill patients	Gut pathogen communities	Ultra-low-diversity gut microbiota associated with pathogen domination during critical illness
Silago et al[29], 2020	Tanzania	Observational cohort	Critical care patients	MDR Gram-negative bacteria	Colonization and environmental contamination contributed to bacteraemia
Padar et al[31], 2021	Estonia	Prospective ICU study	ICU patients	Citrulline/I-FABP	Biomarkers reflected intestinal injury in critical illness
Reintam Blaser et al[33], 2021	Multicentre Europe	Prospective observational study	Critically ill patients	GI dysfunction	Developed gastrointestinal dysfunction scoring system
Chu et al[16], 2022	China	Prospective cohort	ICU patients	CRE	Rectal colonization significantly associated with bloodstream infection
Garcia et al[13], 2022	Spain	Prospective cohort	ICU patients	MDR bacteria/microbiome	Gut microbiome disruption associated with MDR colonization
Mu et al[23], 2022	China	Molecular cohort study	Septic patients	Gut–blood pathogen concordance	Bloodstream pathogens genetically matched gut strains
Falcone et al[41], 2022	Italy	Observational cohort	Severe COVID-19 ICU patients	MDR Klebsiella pneumoniae	Hypervirulent MDR strains spread in ICU population
Baek et al[14], 2023	South Korea	Microbiome analysis	ICU patients	CRE	Dysbiosis associated with CRE colonization
Casale et al[40], 2023	Italy	Cohort study	Hospitalized COVID-19 ICU patients	Carbapenem-resistant organisms	Colonization increased mortality and infection risk
Onuk et al[34], 2023	Turkey	Prospective cohort	ICU patients	Citrulline/I-FABP	Biomarkers correlated with gastrointestinal dysfunction
Tyszko et al[35], 2023	Poland	Observational study	Septic ICU patients	Citrulline/I-FABP	Biomarkers predicted gastrointestinal failure
Molinari et al[25], 2025	International multicentre	Prospective observational study	Septic shock patients	Endotoxin activity	Higher endotoxin activity associated with organ failure and mortality
Yang et al[15], 2025	China	Microbiome study	ICU patients	CRKP	Microbiome diversity associated with colonization resistance
Favier et al[18], 2026	Argentina	Prospective surveillance study	ICU patients	Carbapenem-resistant Enterobacterales	Rectal and extra-rectal colonization predicted subsequent infection
Fang et al[28], 2025	China	Molecular epidemiological study	Hospitalized patients	CRKP	Colonizing and bloodstream isolates showed plasmid and genotypic concordance
Nguyen et al[37], 2025	France	Prospective clinical study	Septic/peritonitis patients	Endotoxin burden/HDL	HDL levels associated with reduced endotoxin burden in sepsis
Lyu et al[27], 2026	China	Prospective cohort	ICU patients	CRE	Genotypic concordance between colonizing and infecting strains

ICU: Intensive care units; ESBL: Extended-spectrum beta-lactamase; GI: Gastrointestinal; MDR: Multidrug-resistant; CRKP: Carbapenem-resistant Klebsiella pneumoniae; I-FABP: Intestinal fatty acid-binding protein; HDL: High-density lipoprotein; CRE: Carbapenem-resistant Enterobacteriaceae; COVID-19: Coronavirus disease 2019.