C. difficile Infection Management (IDSA/SHEA 2021)

Algorithm Steps

1. ▶

   Start

   Suspected C. difficile Infection

   ≥3 unformed stools in 24h + risk factors (antibiotics, hospitalization)

   1. ●

      Action

      Confirm Diagnosis

      Test only diarrheal stool (liquid/take shape of container)

      • NAAT (PCR) alone OR
      • GDH + toxin EIA (two-step) OR
      • NAAT + toxin EIA
      • Do NOT test for cure
      • Do NOT test asymptomatic patients
      1. ●

         Action

         Initial Management

         Start while awaiting results if high suspicion

         • STOP inciting antibiotic if possible
         • Contact precautions
         • Avoid antidiarrheals
         • Avoid PPIs if not strictly indicated
         1. ◆

            Decision

            Assess Severity

            Classify as non-severe, severe, or fulminant

            1. ●

               Action

               Non-Severe CDI

               WBC ≤15,000 AND Cr <1.5

               • Fidaxomicin 200mg PO BID x 10 days (preferred)
               • OR Vancomycin 125mg PO QID x 10 days
               • Avoid metronidazole in adults
               1. ◆

                  Decision

                  High Recurrence Risk?

                  Age ≥65, immunocompromised, severe episode, previous CDI

                  1. ●

                     Action

                     Consider Bezlotoxumab

                     Anti-toxin B monoclonal antibody

                     • Single IV dose during antibiotic treatment
                     • Reduces recurrence by ~40%
                     • High-risk patients: age ≥65, immunocompromised, severe CDI, prior CDI
                     1. ✓

                        Outcome

                        CDI Resolved

                        Resolution = formed stools + no new diarrhea

                  2. ●

                     Action

                     First Recurrence

                     10-25% of patients recur

                     • Fidaxomicin 200mg BID x 10 days (preferred over vanco)
                     • OR Vancomycin taper:
                     • 125mg QID x 10-14d, then
                     • 125mg BID x 7d, then
                     • 125mg daily x 7d, then
                     • 125mg q2-3 days x 2-8 weeks
                     • Consider FMT after
                     1. ●

                        Action

                        Second or More Recurrence

                        FMT strongly recommended

                        • FMT after standard course of vancomycin (preferred)
                        • FMT success rate 80-90%
                        • If FMT not available: extended vancomycin taper + rifaximin
                        • Fidaxomicin extended dosing (every other day weeks 2-4)
                        1. ✓

                           Outcome

                           Prevention Measures

                           Antibiotic stewardship, hand hygiene, probiotics (limited evidence)

            2. ●

               Action

               Severe CDI

               WBC ≥15,000 OR Cr ≥1.5 OR age ≥65 with severe illness

               • Fidaxomicin 200mg PO BID x 10 days (preferred)
               • OR Vancomycin 125mg PO QID x 10 days
               • Consider vancomycin + IV metronidazole if critically ill
            3. ⚠

               Warning

               ⚠️ Fulminant CDI

               Hypotension, shock, ileus, or megacolon

               • Vancomycin 500mg PO/NG QID
               • + Metronidazole 500mg IV q8h
               • + Vancomycin enemas 500mg/100mL NS q6h if ileus
               • Surgical consult STAT
               • Consider colectomy
               1. ⚠

                  Warning

                  Surgical Evaluation

                  For fulminant CDI refractory to medical therapy

                  • Lactate >5, WBC >50,000
                  • Toxic megacolon (colon >6cm)
                  • Peritonitis, perforation
                  • Subtotal colectomy with end ileostomy
                  • OR Loop ileostomy with colonic lavage (may preserve colon)