infectious diarrhea and CDI

Question 1

definition of acute infectious diarrhea

Answer 1

passage of loose or watery stool >=3 times in a 24h period that lasts for <14 days

Question 2

sources of infectious diarrhea

Answer 2

• international trvel
• food or water borne
• exposure to infeced animal or feces
• recent antimicrobial use

Question 3

how is acute infectious diarrhea trasnmitted

Answer 3

likely fecal to oral route

Question 4

what diagnositic testing is doen for acute infectious diarrhea

Answer 4

• lab test not routinely done
• rec in pt with diarrhea with fever, bloody or mucoid stools, severe ab cramping or tenderness, signs of sepsis
• test of salmonella, shigella,cD…

stool culture and PCR done

Question 5

when is ab tx recommended for acute infectious diarrhea?

Answer 5

• pt has severe disease (fever, bloody or mucoid stools, severe ab cramping or tenderness)
• pt appears septic
• pt is immunocomprimised host

Question 6

what is the empiric therapy for AID?

Answer 6

• Ceftriaxone 2g IV q24h
  or
• ciprofloxacin 500mg PO BD
  for 3-5 days

Question 7

what is Clostridioides difficile(C.diff)

Answer 7

• gram pos, anaerobic, sport forming, otxin producing bacillus
• colonize intestinal tract

Question 8

how iare c diff infections caused

Answer 8

facilitated by disruption of norma; intestinal flora

often due to ab therapy

Question 9

what are the clinical manifestations of CDI

Answer 9

• diarrhea without colitis: >= 3 ep of unformed stools in 24h
• colitis: fver, ab pain, nausea, anorexia
• severe colitis: sepsis, sig leukocytosis, renal impairment
• fulminant colitis (severe + complicated): eg. toxic megacolon, colonic perforation, intestinal paralysis

Question 10

risk factors of cdi

Answer 10

pharmacotherapy

• number and days of systemic concomitant ab use
• high risk ab (eg. clindamycin, FQ)
• PPI

past healthcare exposure

• prior hospitalisation
• duration of hospitalisation
• long term care residnecy

host immunity
- lack of ab response to65 yo

C c diff toxin

• severity of underlying illness
• comorb

increasing age
- >65 yo

CDI experience
- prior CDI infection

Question 11

risk factors of cdi

Answer 11

antibiotic

• highest risk during ab tx and 1 month post
• high risk ab: clindamycin, 3/4th gen cephalosporin, FQ
• exposure dep: number, dose and duration of ab

ppi

• reduction of gastric acid may allow ingested c diff to survive
• discont. unnec ppi

Question 12

diagnosis of cdi

Answer 12

• unexplained and new onset diarrhea
  AND
  positive stool test result for toxigenic c diff or its toxins

Question 13

what are the 3 major tests done to diagnose cdi?

Answer 13

• glutamate dehydrogenase GDH EIA: detect c diff common antigen
• toxin A and B EIA: detect toxins a and b
• nucleic acid amplication tests (NAAT): detects c diff toxigenic genes, may detect colonisation and not true cdi

Question 14

how is CDI transmitted

Answer 14

• likely fecal to oral route

- healthcare setting: exposure to contaminated envr or hands of healthcare personnel, transiently contam with spores

Question 15

how is cdi controlled

Answer 15

• isolatio measurs for infected pt
• appropriate PPE when caring for infected pt
• practice good hand hygeien before and after contact with pt
• infection control strategies implemented ine every suspected case, not only confirmed

envr management
- sporicidal disinfectant to cleanse reusable equipment

antimicrobial stewardship
- minimise freq and duration of high risk ab therapy

Question 16

tx for initial episode, non severe CDI

Answer 16

• vancomycin (VAN) 125mg PO q6h for 10 days
• fidazomicin (FDX) 200mg PO q12h for 10 days (not not registered in sg)

alt tx
- metronidazole 400mg PO q8h for 10 days

Question 17

tx for initial episode, severe CDI

Answer 17

• VAN 125mg PO q6h for 10 days
• fidazomicin (FDX) 200mg PO q12h for 10 days
• metronidazole NOT REC

Question 18

tx for initial episode, fulminant CDI

Answer 18

• VAN 500mg PO q6h by mouth or NG tube
• metronidazole 500mg IV q8h

if ileus:

• combi of VAN and metronidazole rec
• consider adding PR VAN 500mg in 100ml NS PR q6h (rectal instillation via enema)

Question 19

what are some advantage of fidaxoamicin vs other CDI tx

Answer 19

• display narrow sepc of activity
• bactericifal (VAN is bacteriostatic)
• lower MIC agaisnt c diff
• prolonged post ab effect, require less frequent dosing
• higher rate of sx cure with FDX
• FDX assc with lower CDI recurrence rate

Question 20

diadvantage of FDX

Answer 20

• expensive
• limited data to support use in complicated cdi
• not registered in sg

Question 21

tx of recurrent episodes of cdi

first recurrence

Answer 21

if metronidazole was used for initial
- VAN 125mg PO q6h for 10 days

if vAN of FDX used
- prolonged tapered or pulsed VAN regimen:
VAN125mg PO q6h x 10-14 days ==>
Van 125mg PO q12h x 7 days==>
VAN 125mg q24h x 7 days ==>
VAN 125mg PO every 2-3 days for 2-8 weeks

if VAN was used for initial
- FDX 200mg PO q12h for 10 days

Question 22

tx of recurrent episodes of cdi

2nd/3rd recurrence

Answer 22

• tapered for pulsed VAN regimen
• VAN 125mg PO q6h x 10 days followed by rifaximin 400mg PO q8h x 20 days
• FDX 200mg PO q12h for 10 days

if failed appropriate ab therapy (for >= 2 recurrences)
- fecal microbiota transplantation: restore gut microbiata diversity via instillation of healthy donor stools into GIT of pt with recurrent cdi

Question 23

how do we monitor therapy of cdi

Answer 23

assess for resolution of sx

• improvement in diarrhea freq and consistency (within few days of initiating tx with near complete resolution within 10 days)
• resolution of leukocytosis
• not rec to repeat stool testing to assess cure (significant proportion woudl test psoitive despite improvement)