C.diff modules (pie) Flashcards
What is C.difficile ?
A spore forming bacteria present in 2-5% of the population which can live with the normal bowel flora without causing harm
What is the microscopic appearance of C.diff?
- Gram positive spore-bearing bacillus
- The spores are more resistant to disinfectants
What is a C.difficile infection ?
- Some antibiotics or enteral feeds can interfere with the balance of normal bowel flora (antibiotics kill both good and bad bacteria) if this is the case C/difficile can multiply and produce toxins which cause illness with symptoms such as diarrhoea
- Known as a C/difficile infection
What are the antibiotics most associated with causing C.difficile ?
- Clindamycin
- Cephalosporins
- Ciprofloxacin
- Co-amoxiclav
The 4 C’s
What is the main risk factor for the development of C/difficile ?
Previous exposure to antibiotics
what is the most common cause of healthcare associated GI infection ?
C.difficile
How may patients squire C.difficile in hospital?
For a patient to get a C.difficile infection what 3 things must occur ?
- Bowel flora must be altered
- Bowel must be colonised with a toxic strain of C.difficile
- C.difficile must then grow and produce its toxins
What is the mechanism of action by which C.difficle causes diarrhoea ?
Organism produces 2 toxins; toxin A (enterotoxin) and toxin B (cytotoxin)
What are the main risk factors for C.difficile infection?
How long after antibiotic treatment commencement do symptoms of C.difficile occur and how late can they present ?
- Usually occur 4-9 days after antibiotic treatment
- Can occur upto 8 weeks after discontinuation of antibiotic treatment
What is the most common symptom of C.diff infection ?
Diarrhoea - sometimes bloody
what are the symptoms of mild C.diff infection (CDI)?
Usually only diarrhoea
what are the additional symptoms for moderate and severe CDI ?
- abdo cramps
- fever
- Raised WCC
- Even more frequent stools
When may other symptoms be present in CDI ?
In severe cases e.g. pseudomembranous colitis, toxic megacolon and peritonitis
Is severe CDI always associated with diarrhoea ?
No - should be suspected in patients showing ileus (bowel obstruction) or sepsis with risk factors of CDI
Define what is meant by diarrhoea
How does CDI spread?
- C.diff produces spores which are released into the environment via faeces
- The main source is the faecal-oral route - indirect/direct contact with an infected person or surface and then touching their mouth/eating the spores
When should treatment for CDI be started ?
Immediately - it should be initiated based on ssymptoms and severity of disease do not wait for microbiology results
How frequently does recurrence of CDI occur ?
20% of the time
What 5 things must you do to prevent cross transmission when an individual has known or suspected CDI?
- Isolate patient if symptomatic - until 48hrs symptom free and bowels returned to normal. After this a terminal clean of patients room done
- Review antibiotic regime
- Use PPE correctly - gloves and apron should be worn prior to each care activity
- Decontaminate equipment and patients immediate environment
- Perform hand hygiene correctly (with warm liquid and soap not alcohol gel)
when is a patient considered to be clear of a CDI ?
- Clear if asymptomatic for 48hrs and bowel habits have returned to normal (specimens to confirm this are not required or accepted by the lab)
- Precautions should continue until these criteria are met
How is C.diff diagnosed ?
- 1st line = Screening test for presence of the organism (GDH)
- 2nd line If GDH positive = test for presence of toxin (toxin A&B)
Screening test neg = negative result
Screening test pos, toxin test pos = positive result
Screening test pos, toxin test neg = indeterminate result = assess patient, send repeat specimen (usually also indeterminate result)
If repeat is indeterminate – clinical decision required!
How is the severity of C.diff assessed ?
Severe if one or more of the following severity markers:
- Temperature > 38.5°C
- Ileus, colonic dilatation >6cm on AXR/CT, toxic megacolon and/or pseudomembranous colitis
- WBC >15 cells x 109 L
- Acute rising serum creatinine >1.5 x baseline
- Has persisting CDI where the patient has remained symptomatic and toxin positive despite 2 courses of appropriate therapy
