Clostridioides difficile (C. diff) is a spore-forming, toxin-producing bacterium that causes antibiotic-associated diarrhea and colitis — from mild loose stools to life-threatening toxic megacolon. In the United States, C. diff causes roughly 500,000 infections and approximately 29,000 deaths annually, making it the most common healthcare-associated infection (HAI) and a critical NCLEX topic. Nurses are the frontline defense: contact precautions, soap-and-water hand hygiene (not alcohol-based hand rub), isolation compliance, stool monitoring, and fluid management are all primarily nursing responsibilities.
This reference covers pathophysiology, risk factors, severity classification, IDSA 2021 treatment guidelines, isolation precautions with the key NCLEX trap (alcohol vs. soap and water), nursing interventions, complications, and six NCLEX-style practice questions.
Fast-scan summary
| Parameter | Key facts |
|---|---|
| Organism | Clostridioides difficile — Gram-positive, spore-forming, anaerobic bacillus; produces Toxin A (enterotoxin) and Toxin B (cytotoxin) |
| Transmission | Fecal-oral; spores survive on surfaces for months; highly contagious in healthcare settings |
| Classic presentation | Watery diarrhea ≥3 loose stools/24h, crampy abdominal pain, low-grade fever, leukocytosis; onset typically within 5–10 days of antibiotic exposure (range: during therapy to 8 weeks after) |
| Severity: non-severe | WBC <15,000 cells/μL AND serum creatinine <1.5× baseline |
| Severity: severe | WBC ≥15,000 cells/μL OR serum creatinine ≥1.5× baseline |
| Severity: fulminant | Hypotension/shock, ileus, or toxic megacolon — surgical emergency |
| First-line treatment (non-severe) | Oral vancomycin 125 mg QID × 10 days (per IDSA 2021 — preferred over metronidazole) |
| Recurrence prevention | Fidaxomicin (Dificid) preferred for first recurrence; bezlotoxumab (Zinplava) monoclonal antibody as adjunct; FMT for ≥2 recurrences |
| Isolation precautions | Contact precautions — gown + gloves; private room preferred |
| CRITICAL hand hygiene rule | Soap and water REQUIRED — alcohol-based hand rub (ABHR) does NOT kill C. diff spores |
| Environmental cleaning | EPA-registered sporicidal agents (bleach-based products, ≥1,000 ppm hypochlorite); standard quaternary ammonium cleaners are ineffective against spores |
| AVOID | Anti-motility agents (loperamide/Imodium) — mask worsening disease and increase risk of toxic megacolon |
What is C. diff and why nurses must know it
C. diff is the most common healthcare-associated infection in the United States, responsible for approximately 500,000 infections annually according to the CDC. It thrives specifically when the normal gut flora is disrupted — most commonly by antibiotics — allowing C. diff to proliferate, produce toxins, and cause colitis ranging from mild self-limiting diarrhea to fulminant colitis with bowel perforation, septic shock, and death.
For nursing students, C. diff hits multiple NCLEX priority areas simultaneously: infection control and isolation precautions, pharmacology (vancomycin vs. metronidazole, fidaxomicin, anti-motility drug contraindications), fluid and electrolyte management, skin integrity, and escalation criteria. The single most tested nursing point is that alcohol-based hand rub does not kill C. diff spores — soap and water is mandatory after caring for C. diff patients.
Pathophysiology
Spore formation and survival
C. difficile is a Gram-positive, obligate anaerobic bacillus. Its ability to form hardy, heat- and chemical-resistant spores is the key to its clinical significance. Spores can survive on environmental surfaces — bed rails, call buttons, bathroom fixtures — for months. They are resistant to most standard hospital disinfectants, including alcohol-based cleaners. Spores are ingested via the fecal-oral route, germinate into vegetative forms in the colon, and colonize the gut.
Disruption of the gut microbiome
In a healthy individual, the normal commensal gut flora (primarily Bacteroides, Lactobacillus, and Bifidobacterium species) competitively inhibit C. diff colonization. Antibiotics — particularly broad-spectrum agents — disrupt this microbial defense. Once colonization resistance is lost, C. diff vegetative cells proliferate and produce their two major toxins.
Toxin A and Toxin B
- Toxin A (TcdA) — enterotoxin: Binds to intestinal epithelial receptors, disrupts tight junctions, triggers an inflammatory cascade with neutrophil recruitment, and causes fluid secretion into the intestinal lumen. This produces the profuse watery diarrhea characteristic of CDI.
- Toxin B (TcdB) — cytotoxin: More potent than Toxin A. Inactivates Rho GTPases, causing cytoskeletal disruption and cell death. Responsible for the destruction of the intestinal epithelium. Both toxins work synergistically; Toxin B is considered the primary virulence factor in severe disease.
Pseudomembranous colitis
In severe CDI, the inflammatory destruction of the colonic mucosa leads to the formation of pseudomembranes — raised yellow-white plaques composed of fibrin, mucus, inflammatory cells, and necrotic epithelium. These plaques coat the colonic mucosa and are visible on colonoscopy. Pseudomembranous colitis indicates significant mucosal destruction and correlates with more severe clinical presentation.
Progression to toxic megacolon
In fulminant disease, the transmural inflammation and paralysis of the colon wall leads to toxic megacolon — colonic dilation >6 cm on plain X-ray with systemic signs of toxicity. The dilated, inflamed colon is at risk for perforation, leading to peritonitis, septic shock, and death. Toxic megacolon is a surgical emergency. For the sepsis progression pathway, see the sepsis nursing reference. For bowel perforation and peritonitis, see the peritonitis nursing reference.
Risk factors
| Risk factor | Mechanism / notes |
|---|---|
| Antibiotic use (highest risk) | Disrupts colonization resistance; highest risk: clindamycin, fluoroquinolones (ciprofloxacin, levofloxacin), cephalosporins (especially 3rd generation); moderate risk: penicillins, carbapenems; lower risk: aminoglycosides, metronidazole, vancomycin |
| Age ≥65 years | Altered immune response, reduced gut microbiome diversity, higher antibiotic exposure, more comorbidities; majority of CDI deaths occur in patients >65 |
| Prior CDI episode | Strongest predictor of recurrence; each episode increases risk of further recurrence by 40–65% |
| Hospitalization / long-term care facility | Environmental spore burden, shared bathrooms, frequent antibiotic use, high-risk patient population |
| Proton pump inhibitor (PPI) use | Reduces gastric acidity; spores are acid-labile at very low pH — PPIs allow more spores to survive gastric passage and reach the colon |
| Immunocompromise | HIV/AIDS, malignancy, chemotherapy, transplant recipients, corticosteroid therapy — impaired immune response allows more extensive toxin-mediated injury |
| Inflammatory bowel disease (IBD) | Disrupted mucosal barrier; 3–8× higher risk than general population; CDI superinfection associated with significantly worse IBD outcomes |
| Gastrointestinal surgery / tube feeding | Altered intestinal motility and microbiome; NG/PEG tubes associated with increased CDI risk, especially if antibiotics given perioperatively |
| Chemotherapy | Direct mucositis + immune suppression + frequent antibiotic prophylaxis — triple hit to colonization resistance |
Clinical presentation
CDI presentation exists on a spectrum from mild diarrhea to life-threatening fulminant colitis. Severity classification drives treatment decisions per IDSA 2021 guidelines.
Non-severe CDI
- Watery, non-bloody diarrhea: ≥3 loose stools per 24 hours
- Diffuse, crampy abdominal pain — often worse after meals
- Low-grade fever (38–38.5°C / 100.4–101.3°F)
- Mild leukocytosis (WBC 10,000–14,999 cells/μL)
- Serum creatinine within 1.5× baseline
- Nausea, malaise, reduced appetite
- Onset typically within 5–10 days of antibiotic initiation; can occur up to 8 weeks after stopping antibiotics
Severe CDI
All of the above plus any of the following:
- WBC ≥15,000 cells/μL — marked leukocytosis suggests significant systemic inflammatory response
- Serum creatinine ≥1.5× baseline — indicates volume depletion or early acute kidney injury
- Increasing abdominal pain and distension
- Profuse diarrhea (may exceed 10 loose stools/day)
- Higher fever
For electrolyte imbalances (hypokalemia, hyponatremia, metabolic acidosis) from stool losses, see the dedicated reference. For lab value interpretation including WBC and creatinine thresholds, see the nursing lab values cheat sheet.
Fulminant CDI (highest severity)
Any of the following:
- Hypotension or septic shock (SBP <90 mmHg, vasopressor requirement)
- Ileus — absence of bowel sounds, abdominal distension, obstipation
- Toxic megacolon — colonic dilation >6 cm on imaging, systemic toxicity
- Bowel perforation (peritoneal signs, free air on X-ray)
Fulminant CDI requires emergent surgical consultation. For the GI bleeding that can complicate pseudomembranous colitis, see the GI bleed nursing reference.
NCLEX tip — recognizing fulminant deterioration
A patient with CDI who suddenly stops having diarrhea and develops abdominal distension and worsening vital signs is a CRITICAL red flag. Cessation of diarrhea in the context of ileus or megacolon indicates the colon is no longer moving — this is deterioration, not improvement. Notify the provider immediately.
Severity classification and treatment
| Severity | Criteria | First-line treatment (IDSA 2021) | Notes |
|---|---|---|---|
| Non-severe (initial episode) | WBC <15,000 cells/μL AND SCr <1.5× baseline | Oral vancomycin 125 mg PO QID × 10 days OR fidaxomicin 200 mg PO BID × 10 days | Vancomycin preferred over metronidazole per 2021 update; fidaxomicin reduces recurrence risk but is more expensive |
| Severe (initial episode) | WBC ≥15,000 cells/μL OR SCr ≥1.5× baseline | Oral vancomycin 125 mg PO QID × 10 days OR fidaxomicin 200 mg PO BID × 10 days | Same agents as non-severe; clinical monitoring for deterioration to fulminant |
| Fulminant CDI | Hypotension/shock, ileus, or toxic megacolon | Oral vancomycin 500 mg QID (high dose) PLUS IV metronidazole 500 mg TID; if ileus: add vancomycin enemas | Emergent surgical consult; subtotal colectomy if medical management fails; bezlotoxumab not used in acute fulminant disease |
| First recurrence | Return of CDI symptoms within 8 weeks of completing treatment | Fidaxomicin 200 mg BID × 10 days (preferred) OR vancomycin taper/pulse regimen | Do NOT re-treat with metronidazole for recurrence; fidaxomicin superior to vancomycin for preventing further recurrence |
| Second or subsequent recurrence | ≥2 prior CDI episodes | Fidaxomicin OR vancomycin taper, PLUS bezlotoxumab (Zinplava) as adjunct; consider FMT referral | FMT (fecal microbiota transplant) most effective for recurrent CDI — 80–90% cure rate for ≥3 recurrences |
Key pharmacology points for NCLEX
Oral vancomycin: For CDI, oral vancomycin acts locally within the gut lumen and is minimally absorbed — it does not achieve systemic levels or treat systemic infection. IV vancomycin has no role in CDI treatment. This is the opposite of vancomycin use for MRSA (IV for systemic infection). See the MRSA nursing reference for contrast.
Metronidazole (Flagyl): No longer recommended as monotherapy for initial non-severe CDI per IDSA 2021 guidelines, due to inferior cure rates vs vancomycin. Reserved for fulminant CDI (IV route, in combination with high-dose oral vancomycin).
Fidaxomicin (Dificid): Narrow-spectrum macrocyclic antibiotic; stays local in the gut; spares Bacteroides and other normal flora more than vancomycin, leading to lower recurrence rates. More expensive than vancomycin — often reserved for recurrent or high-recurrence-risk patients.
Bezlotoxumab (Zinplava): Monoclonal antibody that binds and neutralizes C. diff Toxin B. Given as a single IV infusion during antibiotic treatment. Does not treat active CDI — used to prevent recurrence in high-risk patients (prior CDI, age ≥65, immunocompromise).
Fecal microbiota transplant (FMT): Instillation of processed donor stool (by colonoscopy, enema, or oral capsule) to restore the gut microbiome. Cure rates of 80–90% for recurrent CDI. Not first-line but strongly recommended for patients with ≥2 recurrences.
AVOID anti-motility agents: Loperamide (Imodium), diphenoxylate-atropine (Lomotil), and opioids decrease colonic motility, trapping toxins in the colon and increasing the risk of toxic megacolon. They are contraindicated in CDI.
Diagnostic workup
| Test | Method | Sensitivity / specificity | Nursing notes |
|---|---|---|---|
| Stool PCR (NAAT) | Nucleic acid amplification test for C. diff toxin genes (tcdA/tcdB) | Sensitivity 93–97%; specificity 93–97% — most sensitive single test | Collect unformed stool only (diarrheal consistency); formed stool sample is rejected; document stool consistency before collection; send in sterile container at room temp within 2 hours or refrigerate |
| EIA toxin A/B assay | Enzyme immunoassay detects toxin proteins directly | Sensitivity 63–94%; specificity 93–99% — highly specific but less sensitive than PCR alone | Often used in two-step algorithms with GDH antigen test; false negatives can occur with low toxin concentrations; rapid turnaround |
| GDH antigen assay | Detects glutamate dehydrogenase enzyme (present in both toxigenic and non-toxigenic strains) | High sensitivity (≥90%), low specificity — used as screening step in two-step testing algorithms | Positive GDH requires confirmatory toxin A/B or PCR; negative GDH effectively rules out CDI |
| Two-step algorithm | GDH screening → confirmatory toxin A/B EIA or NAAT | Balances sensitivity (GDH) and specificity (toxin EIA) — most commonly used in clinical practice | Understand the algorithm — intermediate results (GDH+/toxin–) may require clinical judgment or repeat testing |
| Colonoscopy | Direct visualization of pseudomembranes | Gold standard for pseudomembranous colitis; rarely needed when stool testing is diagnostic | Used when stool tests are inconclusive, or for clinical correlation in complex cases; risk of perforation in fulminant disease — discuss with provider |
| WBC (CBC) | Peripheral blood leukocyte count | WBC ≥15,000 indicates severe CDI; markedly elevated WBC (>30,000–50,000) — "leukemoid reaction" — associated with fulminant disease and poor prognosis | Monitor trend; dramatic leukocytosis (>30,000) in a CDI patient warrants urgent provider notification |
| Serum creatinine | Marker of renal function; used in severity classification | SCr ≥1.5× baseline = severe CDI criterion; rising creatinine indicates volume depletion or early AKI | Track baseline SCr; monitor daily in hospitalized patients; escalate rising creatinine to provider |
| Abdominal X-ray / CT | Imaging for complications | Identifies colonic dilation (toxic megacolon: >6 cm transverse colon), free air (perforation), ileus | Prepare patient for imaging if abdominal distension or cessation of diarrhea with worsening clinical status; CT is more sensitive than plain film |
Stool collection nursing priority: Only submit unformed (diarrheal) stool. Do not collect formed stool — labs will reject it as C. diff is unlikely in patients without diarrhea (test-of-cure is not recommended after successful treatment). Do not repeat testing within 7 days unless clinically indicated.
Isolation precautions (NCLEX critical)
Contact precautions protocol
C. diff requires standard precautions PLUS contact precautions:
- Private room preferred — if unavailable, cohort with other confirmed CDI patients; do not cohort with immunocompromised patients
- Gown AND gloves required on room entry — not just for direct patient contact; don before entering, remove before exiting; perform hand hygiene immediately after removing gloves
- Dedicated equipment — dedicated stethoscope, blood pressure cuff, thermometer remain in the room; do not share between patients
- Contact precautions sign on the door — alert all staff and visitors
- Visitor education — teach visitors gown and glove requirements and hand hygiene with soap and water before leaving the room
The single most important NCLEX rule: soap and water, not alcohol
Alcohol-based hand rubs (ABHR) do NOT kill C. diff spores. Spores are resistant to alcohol. After caring for a C. diff patient — or after removing gloves — wash with soap and water for at least 15–20 seconds. Soap and water physically remove spores from hands through friction; they do not kill spores but dislodge them into the water stream.
This is a classic NCLEX trap: options offering “use alcohol hand gel after removing gloves” are incorrect for C. diff. Soap and water is the correct answer every time. For comparison, see the MRSA nursing reference — MRSA is killed by alcohol and does not require soap and water specifically (though soap and water is always acceptable).
Environmental cleaning
Standard quaternary ammonium compounds (quats) — the most common hospital surface disinfectants — do not kill C. diff spores. CDI patients require:
- EPA-registered sporicidal agents: bleach-based disinfectants (sodium hypochlorite, minimum 1,000 ppm / 0.1% concentration; commonly 1:10 dilution of household bleach)
- Enhanced terminal cleaning of rooms after discharge or transfer
- All horizontal surfaces, high-touch areas (call buttons, bed rails, bathroom fixtures, IV poles)
- Disposable cleaning equipment preferred; do not share mop heads or cloths between rooms
Duration of precautions
- Maintain contact precautions for the duration of diarrhea
- Continue for at least 48 hours after diarrhea resolves
- Some institutional protocols extend precautions until discharge, given the risk of residual environmental contamination
- Test-of-cure stool samples are NOT recommended after successful treatment — resolution of symptoms guides discontinuation
Nursing interventions
| Priority | Intervention | Rationale |
|---|---|---|
| 1 — Safety: isolation compliance | Implement contact precautions immediately upon CDI suspicion (do not wait for confirmatory results); gown + gloves on entry; post contact precaution sign; dedicate equipment to the room; educate patient and visitors on precautions | C. diff spreads readily in hospital environments; precautions during the diagnostic window prevent transmission; delays in isolation lead to nosocomial spread |
| 2 — Fluid and electrolyte management | Monitor I&O strictly; assess for dehydration (dry mucous membranes, decreased skin turgor, concentrated urine, tachycardia, hypotension); initiate IV fluid replacement as ordered; monitor daily weights; check electrolytes (Na, K, BUN/Cr) per protocol | Diarrheal losses deplete fluid volume and electrolytes rapidly; hypokalemia is common and can worsen ileus; volume depletion can precipitate AKI. See electrolyte imbalances reference |
| 3 — Stool monitoring | Document frequency, volume, consistency, and color of each stool using a standardized scale (Bristol Stool Scale types 5–7 = diarrhea); note any blood or mucus; collect stool specimen per order (unformed stool only); report sudden cessation of diarrhea with distension | Trending stool frequency tracks treatment response; bloody stool suggests mucosal damage; sudden cessation + distension = ileus/megacolon red flag |
| 4 — Medication administration | Administer oral vancomycin or fidaxomicin as ordered; do NOT administer anti-motility agents (loperamide, diphenoxylate-atropine); hold antidiarrheals and report any orders for them; administer IV metronidazole if ordered for fulminant disease; prepare for vancomycin enemas if ordered for ileus | Anti-motility agents mask disease progression and increase risk of toxic megacolon; vancomycin enemas deliver local drug directly to the colon when ileus prevents oral absorption |
| 5 — Skin integrity | Assess perianal skin with every peri care; apply zinc oxide barrier cream or petroleum-based protectant; use soft, moistened wipes rather than dry toilet paper; consider moisture-wicking underpads; reposition and clean promptly after each stool | Frequent liquid stools cause chemical dermatitis, excoriation, and perineal pressure injury; impaired skin integrity increases infection risk and patient distress |
| 6 — Nutrition support | Maintain oral intake as tolerated (low-fiber, low-residue diet often better tolerated acutely); consult dietitian for patients with poor intake; NPO if toxic megacolon or ileus suspected; avoid foods that worsen motility | Adequate nutrition supports mucosal repair and immune function; gut rest is indicated when surgical emergency is possible |
| 7 — Escalation monitoring | Trending WBC, SCr, vital signs every 4–8 hours (per acuity); notify provider for: WBC rise >15,000, fever spike, worsening abdominal pain, signs of peritoneal irritation (guarding, rigidity, rebound tenderness), new hypotension, tachycardia, sudden diarrhea cessation with distension | Rapid escalation from severe to fulminant CDI can occur within hours; early surgical consultation improves outcomes in fulminant disease. For sepsis escalation criteria, see sepsis nursing reference |
| 8 — Antibiotic stewardship | Review antibiotic orders with the provider: is the antibiotic still necessary? Can the spectrum be narrowed? Document CDI diagnosis in the medication reconciliation so prescribers in future encounters are aware of risk | Continuing non-essential broad-spectrum antibiotics during CDI treatment perpetuates microbiome disruption and worsens CDI; antibiotic stewardship is a national patient safety priority |
| 9 — Patient and family education | Explain C. diff, transmission, and why soap and water (not hand sanitizer) is required; demonstrate donning/doffing PPE for family visitors; teach signs of recurrence (diarrhea returning within 8 weeks of completing treatment); ensure patient understands to inform all future healthcare providers of CDI history; address antibiotic use at home | Patients who understand recurrence risk and transmission prevention are more likely to comply with precautions and seek care promptly at relapse |
Complications and monitoring
| Complication | Signs / symptoms | Monitoring and nursing action |
|---|---|---|
| Dehydration and hypovolemia | Dry mucous membranes, tachycardia, decreased urine output (<0.5 mL/kg/h), hypotension, concentrated urine, elevated BUN/Cr ratio, skin tenting | Strict I&O; daily weights; IV fluid replacement per orders; monitor HR, BP, and urine output hourly in severe CDI; see electrolyte imbalances reference |
| Electrolyte imbalances | Hypokalemia (weakness, cramps, arrhythmias, ileus worsening); hyponatremia (confusion, seizure in severe cases); metabolic acidosis (diarrheal bicarbonate losses) | Monitor BMP/electrolytes per protocol; hold K+ supplements if hyperkalemia; replace K+ IV or PO per orders; monitor cardiac rhythm in hypokalemia; see nursing lab values cheat sheet |
| Toxic megacolon | Colonic dilation >6 cm on X-ray, abdominal distension, cessation of diarrhea (paradoxically), fever, tachycardia, hypotension, decreased or absent bowel sounds | Emergent surgical consultation; NPO; nasogastric decompression as ordered; escalate to provider immediately; prepare for possible emergency colectomy; avoid anti-motility agents — these precipitate megacolon |
| Bowel perforation | Sudden severe abdominal pain, rebound tenderness, guarding and rigidity, absent bowel sounds, free air on X-ray, rapid clinical deterioration | Surgical emergency — immediate provider notification; NPO; IV access; prepare for emergent operating room; see peritonitis nursing reference |
| Sepsis / septic shock | Fever or hypothermia, tachycardia, tachypnea, altered mentation, hypotension, elevated lactate, elevated WBC or leukopenia, oliguria | Initiate sepsis protocol (Sepsis-3 criteria); blood cultures × 2 before antibiotics; IV fluid bolus; vasopressors if MAP <65; broad-spectrum antibiotics; ICU consultation; see sepsis nursing reference |
| Acute kidney injury (AKI) | Rising creatinine (≥1.5× baseline), decreased urine output, elevated BUN, electrolyte disturbances | Monitor creatinine daily; maintain adequate fluid intake; review nephrotoxic medications (NSAIDs, ACE inhibitors, aminoglycosides — hold if AKI developing); dose-adjust renally cleared drugs |
| Recurrent CDI | Return of CDI symptoms (≥3 loose stools/24h) within 8 weeks of completing prior treatment course | Do NOT treat recurrence with metronidazole; use fidaxomicin or vancomycin taper per IDSA guidelines; document recurrence history for future prescribers; refer to infectious disease or gastroenterology for ≥2 recurrences; discuss FMT |
| Malnutrition | Weight loss, muscle wasting, albumin and prealbumin decline, poor wound healing | Nutritional assessment on admission; dietitian consult for significant weight loss or prolonged illness; consider enteral nutrition if oral intake inadequate; avoid long NPO periods unless surgically indicated |
NCLEX-style practice questions
Question 1
A nurse is caring for a patient admitted with confirmed C. difficile infection. After removing gloves following perianal care, which action should the nurse take?
- A. Apply alcohol-based hand rub for at least 15 seconds
- B. Wash hands with soap and water for at least 15–20 seconds
- C. Apply alcohol-based hand rub followed by soap and water
- D. Use hand sanitizer with at least 70% alcohol concentration
Correct answer: B
Rationale: Alcohol-based hand rubs do not kill C. diff spores. Spores are resistant to alcohol-containing products. Soap and water physically removes spores from the hands through friction and rinsing — the mechanical action dislodges spores rather than killing them. This is the most critical nursing knowledge point for C. diff infection control. Options A, C, and D are incorrect because they include or rely on alcohol, which is ineffective against C. diff spores.
Question 2
A patient with C. difficile infection has a WBC of 18,500 cells/μL and a serum creatinine of 1.8 mg/dL (baseline 1.0 mg/dL). Which classification correctly describes this patient?
- A. Non-severe CDI — standard treatment with oral metronidazole
- B. Severe CDI — treatment with oral vancomycin or fidaxomicin
- C. Fulminant CDI — requires emergent surgical consultation
- D. Non-severe CDI — treatment with oral vancomycin 125 mg QID
Correct answer: B
Rationale: Per IDSA 2021 criteria, severe CDI is defined by WBC ≥15,000 cells/μL OR serum creatinine ≥1.5× baseline. This patient meets both criteria (WBC 18,500; SCr 1.8, which is 1.8× the baseline of 1.0). Treatment for severe CDI is oral vancomycin 125 mg QID × 10 days or fidaxomicin — NOT metronidazole (no longer first-line). Fulminant CDI requires hypotension/shock, ileus, or toxic megacolon, which are not described.
Question 3
A nurse enters the room of a patient on contact precautions for C. difficile to deliver oral medications. Which sequence of PPE use is correct?
- A. Apply gloves → enter room → apply gown → administer medication → remove gown → remove gloves → use alcohol hand rub
- B. Apply gown → apply gloves → enter room → administer medication → remove gloves → remove gown → wash hands with soap and water
- C. Enter room → apply gown → apply gloves → administer medication → remove gloves → remove gown → use alcohol hand rub
- D. Apply gloves → enter room → administer medication → remove gloves → use alcohol hand rub → remove gown
Correct answer: B
Rationale: Contact precautions require donning gown THEN gloves outside the room, before entry. On exit: remove gloves first (most contaminated item), then gown, then perform hand hygiene with soap and water — not alcohol-based hand rub, as alcohol is ineffective against C. diff spores. Option A has incorrect donning order (gloves before gown). Option C violates the rule against entering the room before donning PPE. Option D is incorrect in both sequence and hand hygiene method.
Question 4
A patient with severe C. difficile infection who has been having 8–10 liquid stools per day suddenly reports that diarrhea has stopped. The nurse assesses abdominal distension, absent bowel sounds, and fever of 39.2°C. What is the nurse’s priority action?
- A. Document the improvement in stool frequency as a sign of treatment response
- B. Administer loperamide (Imodium) as needed for diarrhea control
- C. Notify the provider immediately — these findings suggest toxic megacolon
- D. Obtain a repeat stool C. diff PCR to assess for test-of-cure
Correct answer: C
Rationale: Cessation of diarrhea in a patient with severe CDI combined with abdominal distension, absent bowel sounds, and fever is a critical red flag for toxic megacolon or ileus — not improvement. The colon is failing to propel stool, and the dilation creates risk of perforation and septic shock. Immediate provider notification and imaging are required. Loperamide (Option B) is contraindicated in CDI and would worsen toxic megacolon. Test-of-cure stool testing (Option D) is not recommended by IDSA after CDI treatment.
Question 5
A provider orders a stool specimen for C. difficile testing. When the nurse enters the patient’s room, the patient reports having a formed bowel movement. What should the nurse do?
- A. Collect the formed stool immediately and send it to the lab in a sealed container
- B. Document the stool as formed and do not collect at this time; inform the provider
- C. Add water to the stool sample to approximate a liquid consistency before sending
- D. Collect the formed stool only if the patient also has abdominal cramping
Correct answer: B
Rationale: C. diff PCR and toxin assays should only be performed on unformed (diarrheal) stool. Formed stool testing yields high rates of false positives because C. diff may be present as a colonizer without causing active infection in patients who have formed stool. Labs typically reject formed stool samples. The nurse should document the stool consistency, not collect the specimen, and inform the provider that the patient currently has formed stool. Adding water (Option C) is inappropriate and would adulterate the specimen.
Question 6
A nurse is discharging a patient who was hospitalized with C. difficile infection. Which statement by the patient indicates the need for further teaching?
- A. “I should tell any future healthcare providers that I had C. diff.”
- B. “If I get diarrhea again in the next two months, I should see a doctor right away.”
- C. “I can use my regular hand sanitizer when I get home — that will prevent spreading it to my family.”
- D. “I should avoid unnecessary antibiotics in the future.”
Correct answer: C
Rationale: This statement requires correction. Alcohol-based hand sanitizers do not kill C. diff spores. The patient should be instructed to wash hands with soap and water after using the toilet and before preparing food to reduce fecal-oral transmission to household contacts. Bathroom surfaces should be cleaned with bleach-based products. Options A, B, and D all reflect accurate understanding: informing future providers of CDI history prevents prescribers from inadvertently re-exposing the patient to high-risk antibiotics; recurrence within 8 weeks is common and requires prompt treatment; antibiotic stewardship reduces CDI risk.
Key takeaways for nursing practice
- C. diff is a healthcare crisis: 500,000 US infections/year, primarily driven by antibiotic disruption of the gut microbiome and hospital environmental spore burden.
- Isolation is immediate: Apply contact precautions on suspicion, before confirmatory testing returns.
- Soap and water is non-negotiable: Alcohol hand rub will not remove or kill spores — wash with soap and water after every patient contact.
- Vancomycin beats metronidazole: Per IDSA 2021, oral vancomycin (not metronidazole) is first-line for all CDI — non-severe, severe, and as backbone of fulminant regimens.
- Never give anti-motility agents: Loperamide and diphenoxylate are contraindicated — they can precipitate toxic megacolon.
- Watch for the paradox: Diarrhea stopping in a CDI patient can mean ileus or megacolon — escalate immediately.
- Recurrence is common: Each episode increases the risk of another by 40–65%; fidaxomicin and FMT are tools for recurrent disease.
References: CDC. Clostridioides difficile (C. diff). Accessed 2026. Kelly CP, Lamont JT. Clostridioides difficile in adults: Treatment. UpToDate. 2024. McDonald LC, et al. Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA). Clin Infect Dis. 2018;66(7):e1-e48. IDSA. 2021 Update on CDI Treatment Guidelines. Johnson S, et al. Clin Infect Dis. 2021;73(5):e1029-e1044. Surawicz CM, et al. Guidelines for diagnosis, treatment, and prevention of Clostridium difficile infections. Am J Gastroenterol. 2013;108(4):478-498.