C. Difficile

Question 1

Describe C. diff

Answer 1

-Spore forming anaerobic bacterium
-Toxin and non-toxin producing strains
-Normal bowel flora in infants
-Widespread in nature – water, soil, animal dung (eg. cows, horses, pigs, dogs, cats)
-(Food)
-Health-care environments= spores+++

Question 2

Transmission and ecology

Answer 2

-Asymptomatic colonisation
=Toxin positive strains 3% healthy adults
=Toxin negative strains 3%
=Infants 70%
-20-40% hospital in-patients colonised
-Spores persist in environment
-Faecal-Oral acquisition from (HCW & patient) hands, environment, equipment, other patients

-Relapse common >25%, approx 15% patients die within 30 days of diagnosis

Question 3

Spectrum of disease

Answer 3

-Colonisation of large bowel
-Self-limiting diarrhoea
-Severe/ prolonged/ relapsing diarrhoea
-Pseudomembranous colitis
-Toxic megacolon, bowel perforation and life-threatening sepsis
-Death

Question 4

Pathogenesis of c. diff

Answer 4

-Disturbance of normal competing bowel
flora, usually by antibiotic. Faecal-oral spread
-Ingestion of C.difficile spores germinate in the presence of bile acids
-Colonisation by toxin-producing strain
-Spores germinate= vegetative C.diff –2 important toxins A and B (damage colonic epithelial cells= inflammatory response)
-Cytotoxic and induce host inflammatory
response
-Host factors (immune status, antitoxin antibodies)

Question 5

Disrupted flora/ microbiome

Answer 5

-Bowel flora altered several months after antibiotics
=Susceptible

Question 6

Hospital antibiotic prescribing

Answer 6

~1/3 unnecessary
-Excess duration
-Not susceptible to antimicrobial
-Rx non-infectious / non-bacterial
syndromes
-Rx colonisation / contamination
-Excess or overlapping spectrum
-Documentation poor
-Inappropriate route, dose or timing

Question 7

Antibiotic duration

Answer 7

-Increased duration increases risk
=Repeated courses
=Prolonged courses
=Broad spectrum antibiotics

Question 8

C.diff greatest risks (4C)

Answer 8

-Cephalosporins
-Ciprofloxacin
-Clindamycin
-Co-amoxiclav
-Piperacillin- tazobactam

Question 9

Preferred choices of antibiotic

Answer 9

-benzylpenicillin, flucloxacillin
-amoxicillin
-gentamicin
-vancomycin
-doxycycline
-metronidazole (for anaerobes)

Question 9

Other medication risk factors for c.diff

Answer 9

-Immunosuppression, including chemotherapy and organ transplant patients
-Proton pump inhibitors and other acid suppression agents
-H2 receptor antagonists
-Laxatives (incorrectly assume diarrhoea)

Question 10

Other risk factors for c.diff

Answer 10

-Prolonged or repeated hospital stay
-Comorbidities (including immunosuppression)
-GI surgery (abdominal)
-Enteral (NG or PEG) feeding
-Previous C.difficile
-Age

Question 11

Demographics of C.difficile

Answer 11

-Age= risk greatly increased after 75 and further still in 85+ age group

Question 12

Mandatory surveillance UK (lab testing and reporting)

Answer 12

-Diarrhoeal stools taking the shape of the container, not diagnosed in preceding 4 weeks
-England since 1/1/04 (initially >65 yrs)– after April 2007 >2 years
-Scotland since 1/9/06 – testing all
patients >65 years
– since April 2009 testing all patients 15-64
years
– from Oct 2016 >3 years

Question 13

Diagnostics

Answer 13

-Do not test asymptomatic
-No test of cure/follow up

->3 stools grade 5, 6 or 7 in 24 hrs and C.difficile positive toxin test
-2 step testing
– GDH (glutamate dehydrogenase, screening test, detects strain that are not toxigenic)
– Toxin
-Sigmoidoscopy/colonoscopy= pseudomembranous colitis

Question 14

Ribotype 027

Answer 14

-Outbreaks incl in UK
-Increase in severe
presentations
=Toxic megacolon, colonic
perforation
=More deaths
-Epidemic spread
– <1% in 1995
– 55% 2007 in England

Question 15

Infection control measures

Answer 15

-Pre-emptive isolation
-Own toilet/ commode
-Dedicated equipment
-Bristol stool chart

Question 16

CDI case management

Answer 16

-Assess severity daily
-Review drug chart – stop –
– current antibiotics
– laxatives
– antimotility agents (opiates, loperamide)
– review other medicines eg diuretics, NSAIDs, ACE inhibitors, PPI and H2 blockers
-Supportive care – fluid balance, electrolytes, nutrition
-Consider abdo imaging / surgical / GI opinion

Question 17

Severe C.diff

Answer 17

• WBC >15
• Creatinine rising 1.5 x
  baseline
• Fever >38.5°C
  -Raised lactate
• Suspicion of colitis, ileus or
  toxic megacolon
• Colits on CT scan or X Ray

Question 18

Life threatening C.diff

Answer 18

• WBC >35 or <2
• Lactate >2.2 mmol/l
• Ileus
• Significant abdominal
  distension
• Hypotension
• Altered mental state
• Renal failure
• Respiratory failure
• ICU admission

Question 19

Treatment

Answer 19

-Supportive care is very important - patients diagnosed with C.difficile have a high mortality.
-Standard treatment is oral or NG vancomycin.
-Oral metronidazole is no longer recommended.
-IV vancomycin is ineffective (doesn’t reach colon) and is NEVER used in the treatment of C.difficile.
-Ensure prescribed treatment is actually being taken by the patient.

Question 20

Treatment for very severe infection

Answer 20

-Oral/NG vancomycin higher dose AND IV metronidazole
-Consider colectomy
-Contact microbiology
=Vancomycin enema
=Immunoglobulin

Question 21

Relapse treatment

Answer 21

-Fidaxomicin

Question 22

Describe the faecal microbiota transplant

Answer 22

-80% success
-3+ episodes of C diff
-Extensive donor screening
-Long term effects unknown
-Reports of infection pathogenic E Coli
-Cost?