C. diff | Notion

Clostridioides difficile

Clostridioides difficile is a Gram positive rod often encountered in hospital practice. It produces an exotoxin which causes intestinal damage leading to a syndrome called pseudomembranous colitis.

C. difficile develops when the normal gut flora are suppressed by broad-spectrum antibiotics. Clindamycin is historically associated with causing C. difficile but the aetiology has evolved significantly over the past 10 years. Second and third-generation cephalosporins are now the leading cause of C. difficile.

Other than antibiotics, risk factors include:

proton pump inhibitors

Pathophysiology

anaerobic gram-positive, spore-forming, toxin-producing bacillus
transmission: via the faecal-oral route by ingestion of spores
releases two exotoxins (toxin A and toxin B) that act on intestinal epithelial cells and inflammatory cells resulting in colitis

Features

diarrhoea
abdominal pain
a raised white blood cell count (WCC) is characteristic
if severe toxic megacolon may develop

The Public Health England severity scale is often used as this may determine treatment:

Mild	Moderate	Severe
Normal WCC	↑ WCC ( < 15 x $10^9$/L)
Typically 3-5 loose stools per day	↑ WCC ( > 15 x $10^9$/L) or an acutely ↑ creatinine (> 50% above baseline) or a temperature > 38.5°C or evidence of severe colitis (abdominal or radiological signs)	Hypotension
Partial or complete ileus
Toxic megacolon, or CT evidence of severe disease

Diagnosis

is made by detecting C. difficile toxin (CDT) in the stool
C. difficile antigen positivity only shows exposure to the bacteria, rather than current infection

Clostridioides difficile

Management