When Does Clostridioides difficile "Recur"? Reconcile Epidemiologic & Bedside Recurrent CDI definitions.

Abstract

Recurrent Clostridioides difficile infection (CDI) is a clinical syndrome, a trial endpoint, and a surveillance construct. Epidemiologic and administrative datasets count repeat positive tests or coded episodes, but conflate colonization or test of cure with recurrence. Trials operationalize recurrent CDI with symptoms, testing, but have variable follow-up. Clinically, recurrent CDI requires response, and recurrent illness excluding post-infection bowel dysfunction and mimics. Relapse and reinfection remain difficult to distinguish without strain typing which is more relevant for research. We propose a pragmatic lens: explicitly name the definition used, match it to the decision, and adjudicate clinical recurrence before escalating therapy.