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

Figure 1 PRISMA flow diagram illustrating the study identification and selection process for the systematic review. ¹Records were identified through a systematic search of the PubMed (MEDLINE), EMBASE, Cochrane Library database (2000-2025) using predefined keywords and manual screening of reference lists of relevant articles. ²No automation tools were used; all records were screened manually by the authors. ICU: Intensive care units. Adapted from Page et al[26].

Figure 2 Conceptual model of gut barrier dysfunction and multidrug-resistant bacterial translocation in critical illness. Critical illness is associated with intestinal epithelial injury characterized by tight junction disruption, mucosal inflammation, and altered intestinal permeability. Antibiotic exposure and physiological stress are associated with microbiome dysbiosis and reduced colonization resistance, which may permit expansion of multidrug-resistant organisms such as carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Klebsiella pneumoniae, and vancomycin-resistant Enterococcus. These processes are hypothesized to contribute to bacterial translocation and endotoxin release into the bloodstream, potentially leading to systemic infection and sepsis. This model represents a conceptual integration of mechanistic and clinical evidence derived from observational studies and should not be interpreted as establishing a definitive causal path. MDR: Multidrug-resistant; CRE: Carbapenem-resistant Enterobacteriaceae; CRKP: Carbapenem-resistant Klebsiella pneumoniae; VRE: Vancomycin-resistant Enterococcus; I-FABP: Intestinal fatty acid-binding protein.