Pet Ownership Protects Against Recurrence of Clostridioides difficile Infection

Clostridioides difficile infection (CDI) is the leading cause of antibiotic-associated and health care-associated diarrhea in humans. Recurrent CDI (R-CDI) occurs in ~20%-30% of patients with CDI and results in increased morbidity, mortality, and hospital costs. Genomic analyses have shown overlap of C. difficile isolates from animals and people, suggesting that a zoonotic reservoir may contribute to recurrence. The objective of this study was to determine whether pet ownership is a risk factor for recurrence of CDI.

We conducted a case-control study among patients with recurrent CDI (cases; n = 86) and patients with nonrecurrent CDI (controls; n = 146). Multivariable logistic regression modeling was used to determine the association between recurrence of CDI and pet ownership while accounting for patient-level risk factors.

Pet ownership was not significantly associated with recurrence of CDI (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.38-2.72; P = 0.965) among all patients (n = 232). However, among the subset of patients with community-associated or community-onset health care facility-acquired CDI (n = 127), increasing contact with pets was increasingly protective against recurrence: for every point increase in a pet contact score (out of 7 possible points), the odds of recurrence decreased by 14% (OR, 0.86; 95% CI, 0.74-1.00; P = 0.051).

Close interactions with pets appear protective against the recurrence of community-acquired CDI. A potential mechanism may involve beneficial contributions to the microbiota of pet owners afflicted with CDI, as has been observed for other conditions such as atopy, obesity, and food allergies. However, more research is needed to understand the interactions between pets, owners, and their microbiota.