Clostridioides difficile infection (Clostridioides difficile; C. difficile)

A confirmed Clostridioides difficile infection (CDI) case is a patient two years or older, to whom one or more of the following criteria applies:

• Diarrhoeal* stools or toxic megacolon, with either
  
  • Positive laboratory assay for C. difficile toxin A (TcdA) and/or toxin B (TcdB) in stools or
  • Toxin-producing C. difficile organism detected in stool via culture or other means
• Pseudomembranous colitis revealed by lower gastrointestinal endoscopy
• Colonic histopathology characteristic of C. difficile infection (with or without diarrhoea) on a specimen obtained during endoscopy, colectomy or autopsy

* Diarrhoea is defined as three or more loose/watery bowel movements (which are unusual or different for the patient) in a 24-hour period

New case of CDI

• A patient with a first episode of CDI meeting the criteria above or
• A patient with a subsequent episode of CDI meeting the criteria above, with onset of symptoms more than eight weeks after the onset of a previous episode

Recurrent case of CDI

• A patient with an episode of CDI that occurs within eight weeks following the onset of a previous episode provided that CDI symptoms from the earlier episode resolved with or without therapy

Case classification

A. Possible case
NA
B. Probable case
NA
C. Confirmed case
Any person meeting the criteria outlined above for a new or recurrent case

Notes:

1. Diarrhoea is defined as three or more loose/watery bowel movements that take up the shape of their container (which are unusual or different for the patient) in a 24 hour period
2. The current international C. difficile case definition excludes (i) cases where diarrhoea is thought to be due to different aetiology (as diagnosed by the attending physician) and (ii) asymptomatic patients with a stool culture positive for toxin-producing C. difficile or an assay positive for C. difficile toxin (TcdA and /or TcdB)

Additional definitions for enhanced C. difficile infection (CDI) surveillance

ONSET

• Healthcare onset » Symptoms start during a stay in a healthcare facility
• Community onset » Symptoms start in a community setting, outside healthcare facilities
• No information available » If no information was available on location of patient at onset of symptoms

ORIGIN

• Healthcare-associated case» This is a CDI patient with either
  • Onset of symptoms at least 48 hours following admission to a healthcare facility (healthcare-onset, healthcare-associated) or
  • Onset of symptoms in the community within four weeks following discharge from a healthcare facility (community-onset, healthcare-associated)
• Community-associated case» This is a CDI patient with either
  • Onset of symptoms while outside a healthcare facility and without discharge from a healthcare facility within the previous 12 weeks (community-onset, community-associated) or
  • Onset of symptoms within 48 hours following admission to a healthcare facility without residence in a healthcare facility within the previous 12 weeks (healthcare-onset, community-associated)
• Discharged 4 – 12 weeks from a healthcare facility» This is a CDI patient who was discharged from a healthcare facility between four and 12 weeks before the onset of symptoms
• No information available» If no information was available on origin of infection

Severe case of CDI
This is a CDI patient to whom any of the following criteria apply:

• Admission to an intensive care unit for treatment of CDI or its complications (e.g. for shock requiring vasopressor therapy)
• Surgery (colectomy) for toxic megacolon, perforation or refractory colitis
• Death within 30 days after diagnosis, if CDI is either the primary or a contributive cause

Last updated: July 2023