Antimicrobial therapy can lead to disruption of the gut microbiome and infection with Clostridioides difficile, a disease associated with high morbidity and mortality, particularly among the elderly. Drawing on observations that pet ownership and close contact with pets are protective against colonization with C. difficile and recurrence of C. difficile infection, the proposed study will test the hypothesis that microbiota that provide colonization resistance against C. difficile are shared between patients and their pets and that pet contact can mitigate antimicrobial-associated gut dysbiosis and the risk of C. difficile infection. This study will further define epidemiologic and pathophysiologic characteristics of C. difficile infection and gut microbiome dysbiosis that could enhance therapeutic options for these conditions, potentially through non-invasive interventions involving animal contact.