A controlled human infection model for Clostridiodes difficile

Clostridiodes difficile infection (CDI) remains a substantial public health issue, despite some recent reductions in healthcare-associated CDI.(1) Antimicrobial resistance is emerging(2), and relapse/recurrence is increasing (3).  Although often considered a healthcare-associated infection, community-acquired CDI is becoming more frequent. (3)  Asymptomatic colonisation with vegetative bacteria or spores is common, with triggers for development of symptomatic disease including disruption of the microbiota by antibiotics, gastric acid suppression, or other concurrent illness and aging. (3, 4) Cases may be associated with faeco-oral transmission of spores or vegetative bacteria, but may also be due to germination of spores already carried by an individual. Diagnosis preferably involves a two-stage process. Firstly, detection of Clostridiodes difficile in stools by a sensitive method such as PCR or detection of glutamate dehydrogenase antigen(GDH)(3). However, asymptomatic colonisation is common, and an additional, more specific method for Clostridiodes difficile actively producing toxin enables more accurate diagnosis. (3) Such methods include a...