[Role of the gut microbiome in the development and transfer of antibiotic resistances]

Antimicrobial resistance (AR) is a natural phenomenon resulting from the exposure of bacteria to antibacterial substances. The intestinal microbiome plays a central role in the development and transmission of AR. In its physiological state, the intestinal microbiome has several mechanisms that contribute to what is referred to as colonization resistance against potentially pathogenic and often multiresistant bacteria. Exposure to broad-spectrum antibiotics can disrupt those mechanisms, facilitating colonization with these pathogens. The persistence of antibiotic selection pressure favors growth of multiresistant bacteria and their dominance within the intestinal microbiota. Under these circumstances, the risk of the development of invasive infections increases. Antibiotic stewardship programs, the use of narrow-spectrum antibiotics, and the administration of substances that protect the intestinal microbiome from antibiotic exposure can prevent these processes. Several interventions such as the administration of probiotics, oral antibiotics, and fecal microbiome transfers are potential strategies for decolonizing patients with multidrug resistant bacteria; to date, however, no intervention has been proven to be consistently effective.