CDAD Infections

Question 1

Describe the pathogenesis of CDAD infections

Answer 1

Colonization of intestinal trace with C.difficile occurs

Antibiotics disrupt barrier function of normal colonic flora and allow C.difficile to multiply and produce toxins

Production of toxins A and B lead to inflammation and diarrhea

Question 2

What are the patient risk factors associated with CDAD?

Answer 2

Age > 65
Multiple or severe comorbidities
Immunosuppression
History of CDI
GI surgery
Tube feeding

Question 3

What are some healthcare exposure risk factors associated with CDAD?

Answer 3

Prior hospitalization in last 1 year
Duration of hospitalization
Residence in nursing homes / long term care facilities
Use of antibiotics
Use of gastric acid suppressive therapy

Question 4

List the antibiotics that increase and decrease risk of CDAD

Answer 4

Increase: Clindamycin, 3rd/4th gen cephalosporins, fluoroquinolones

Decrease: Tigecycline and doxycycline

Question 5

What are the strategies of antimicrobial stewardship used to prevent CDAD infections?

Answer 5

Isolation
- Accommodating patients with CDI to private room with dedicated toilet
- If limited number, either only prioritize patients with stool incontinence for placement in private room OR isolate those with CDI in one room together

Hand hygiene
- Wear gloves and gowns
- Preferred handwash with soap and water

Environmental cleaning using sporicidal agent

Decrease frequency and duration of high risk antibiotic therapy

Decrease number of antibiotic agents

Question 6

What are other non-antibiotic modalities to consider?

Answer 6

Acid suppression (limit use of PPI)

Provide probiotics

Question 7

What is the main clinical presentation of CDAD?

Answer 7

Watery diarrhoea with more than 3 loose stools in 24 h

Question 8

What are the usual symptoms of mild CDAD?

Answer 8

Diarrhea
Abdominal cramps

Question 9

What are the symptoms of moderate CDAD? What are some of the lab results to support a moderate CDAD diagnosis?

Answer 9

Fever
Diarrhea
Nausea
Malaise
Abdominal cramps and distension

Lab Results:
Leukocytosis
Hypovolemia

Question 10

What are the symptoms for severe CDAD? What are the lab parameters supporting this diagnosis?

Answer 10

Fever
Diarrhea
Diffused abdominal cramps and distension

Lab parameters:
- WBC > 15 x 10 9/L
- SCr > 133 mcmol/L

Question 11

What are the symptoms of fulminant CDAD?

Answer 11

Hypotension / shock

Ileus

Megacolon

Question 12

What are the indications for CDI testing?

Answer 12

Symptomatic patients with more than 3 unformed stools per day

Question 13

What are the types of CDI testing and their limitations?

Answer 13

NAAT and PCR
- Unable to differentiate if genes are activated and toxins are produced
- Identifies genes producing toxin A and B

EIA

GDH immunoassays: cannot differentiate type of C.difficile

Question 14

What are some DO NOT of CDI testing?

Answer 14

Do not repeat testing < 7 days

DO not repeat test to document cure

Question 15

What do I do if patient is currently on other additional antibiotic therapy?

Answer 15

Discontinue any antibiotic therapy not specifically treating CDI

Question 16

What if patient is unable to discontinue their additional antibiotic therapy?

Answer 16

Select narrowest agents

Avoid agents that increase risk of CDI

Question 17

What is the treatment for non-severe CDI for an initial episodes of CDI?

Answer 17

PO Vancomycin 125mg QDS

Question 18

What is the alternative treatment for non-severe CDI for an initial episodes of CDI?

Answer 18

PO Metronidazole 400mg TDS

Question 19

What is the treatment for severe CDI for an initial episodes of CDI?

Answer 19

PO Vancomycin 125mg QDS

Question 20

What is the treatment for fulminant CDI for an initial episodes of CDI?

Answer 20

IV Metronidazole 500mg q8h + PO Vancomycin 500mg QDS + PR Vancomycin

Question 21

What are the risk factors for recurrent episodes of CDI?

Answer 21

Administration of other antibiotics during / after initial treatment of CDI

Defective humoral responses against C.difficile toxins

Advancing age

Severe underlying disease

Continued use of PPI

Question 22

What is the treatment for a recurrent episodes of CDI if vancomycin was used for an initial episode of CDI ?

Answer 22

PO Vancomycin tapered
- 125mg QDS x 10-14 days
- 125mg BD x 7 days
- 125mg daily x 7 days
- 125 mg every 2-3 days for 2-8 weeks

Question 23

What is the treatment for a recurrent episodes of CDI if metronidazole was used for an initial episode of CDI ?

Answer 23

PO Vancomycin 125mg QDS for 10 days

Question 24

What is the ideal duration of treatment?

Answer 24

10-14 days