Fidaxomicin First, FMT Future in C. Difficile Colitis: Mastering CDI Diagnosis, Recurrence Prevention, and the Microbiome Shift

In this episode of Hospital Medicine Unplugged, we tackle Clostridioides difficile infection (CDI) on the wards—fast, practical, guideline-driven care from test ordering to recurrence prevention.

We open with the first moves: test only the right patient—≥3 unformed stools in 24 h (or ileus/toxic megacolon). Use a two-step algorithm: GDH + toxin EIA up front; NAAT as the tiebreaker if discordant. No “test of cure.” While labs cook, fix the basics: stop the inciting antibiotic if you can (or narrow), review meds (especially PPIs), start IV fluids/electrolytes, and avoid antimotility agents in severe/fulminant disease. Early nutrition, VTE prophylaxis, and pain control (skip NSAIDs in bad colitis).

Then the therapy that actually changes outcomes—start early, pick right:
Initial episode (non-severe or severe, non-fulminant):
• Fidaxomicin 200 mg PO BID x10 days (preferred for lower recurrence).
• Vancomycin 125 mg PO QID x10 days (solid alternative).
• Metronidazole is out as first-line.

Fulminant CDI (hypotension/shock, ileus, megacolon):
• Vancomycin 500 mg PO/NG QID + metronidazole 500 mg IV q8h.
• If ileus, add rectal vancomycin enemas 500 mg q6h.
• Early surgical consult—don’t wait on deterioration.

Risk tools & who gets extras: clock the high-recurrence patients (≥65, severe CDI, immunocompromise, IBD, CKD, episode within 6 months, on concomitant antibiotics). For them, consider bezlotoxumab 10 mg/kg IV once during treatment to cut recurrence.

Recurrence playbook:
• First recurrence: fidaxomicin again or vancomycin taper/pulse.
• Multiple recurrences: fecal microbiota–based therapy (FMT or FDA-approved live biotherapeutics) after guideline-directed antibiotics.
• Keep stewardship tight; re-audit PPIs/antibiotics at every turn.

Infection prevention that actually prevents: enteric contact precautions (gown/gloves), soap-and-water hand hygiene on exit, and sporicidal (bleach) cleaning for rooms and gear. Educate patients on hygiene and what recurrence looks like.

Rescue moves & ICU cues: escalating lactate/organ failure, peritonitis, perforation, or toxic megacolon? Get surgery and critical care to the bedside. Subtotal colectomy with end ileostomy is standard; diverting loop ileostomy with colonic lavage in selected high-risk cases. In the ICU: hemodynamics, serial abdominal exams, frequent labs/imaging, multidisciplinary huddles.

Special situations you’ll see:
• IBD: higher severity/recurrence—favor fidaxomicin; coordinate with GI, avoid reflex steroid escalation until CDI is controlled.
• Elderly/CKD: higher recurrence—strong case for bezlotoxumab; be meticulous with fluids/electrolytes.
• Heme/Onc & Transplant: prolonged shedding, drug interactions—early ID consult; plan recurrence prevention up front.

Monitoring & discharge that sticks: expect symptom improvement in 48–72 h; if not, reassess for ileus/megacolon or a missed diagnosis. Don’t re-test for cure—follow the clinical course. Discharge with a documented episode/severity, drug/dose/duration, recurrence-prevention plan (stewardship, PPI review, bezlotoxumab/FMT when indicated), clear return precautions, and early follow-up.

Concise, high-yield, and system-savvy—everything your team needs to deliver safer, more effective inpatient CDI management.