Understanding the Pathophysiology of Clostridioides difficile Infection, Colonization, and Making an Accurate Diagnosis.

Clostridioides difficile is a gram-positive bacterium and major cause of infectious colitis, in hospital and health care settings, where it remains a significant public health threat. Accurate diagnosis of C difficile infection (CDI) is challenging and requires a clinical assessment supported by laboratory stool testing. Reliance on laboratory tests can lead to both overdiagnosis and underdiagnosis. This article outlines the pathophysiology of C difficile, with emphasis on aspects related to diagnostic testing, and discusses the clinical approach to clinical diagnosis. New therapies for the treatment and prevention of CDI all rely on accurate clinical and laboratory identification of true infection.