Pathogen suppression via competitive exclusion

Pathogen suppression via competitive exclusion refers to an ecological and microbiological phenomenon where resident, beneficial, or commensal microbes prevent colonization or proliferation of pathogenic organisms by outcompeting them for resources, producing inhibitory compounds, or occupying physical niches. This process is a cornerstone of the “colonization resistance” observed in healthy microbiomes of animals and humans, and is exploited in therapeutic strategies such as fecal microbiota transplantation or probiotic administration to prevent infections like *Salmonella*, *Clostridioides difficile*, or pathogenic *E. coli*. It is not a single molecule, protein, or receptor, but rather a multifaceted community-level mechanism[1][3][9].

Other names

Competitive exclusionColonization resistanceMicrobial interferenceNiche competition

Nutrient competition (commensals deplete resources required by pathogens) Production of inhibitory metabolites (e.g., short-chain fatty acids, bacteriocins) Occupation of ecological niches, preventing pathogen adhesion[1][3][9] Modulation of host immune response (indirectly suppressing pathogen colonization)