Gut pathogen colonization

Gut pathogen colonization refers to the process by which pathogenic microorganisms—such as bacteria like *Salmonella*, *Clostridioides difficile*, or antimicrobial-resistant *Klebsiella pneumoniae*—establish and proliferate within the gastrointestinal tract[1][2][3][4][5]. Colonization is modulated by factors including microbiota composition, immune responses, availability of nutrients, host genetic factors, and external pressures such as antibiotics. Healthy gut microbiota exert colonization resistance, directly killing pathogens, competing for resources, and stimulating protective immune responses. Disruption of this balance (e.g., following antibiotics, dietary change, or illness) increases susceptibility to pathogen overgrowth, leading to infection and associated disease states[1][2][4][5].

Other names

Pathogen colonization in the gutColonization resistance (inverse phenomenon)Intestinal pathogen colonization

Disruption or restoration of colonization resistance by antibiotics or probiotics; Direct inhibition or killing of pathogens (*via* antimicrobials); Modification of microbiota composition (*via* transplantation or bacteriophage therapy)