Multisystem Processes & Disorders

Healthcare-associated infections: prevention bundles

Clinical Overview and When to Suspect Healthcare-Associated Infection

— CLABSI — central line-associated bloodstream infection (line in place >2 calendar days)

— CAUTI — catheter-associated urinary tract infection (Foley >2 days)

— VAP/VAE — ventilator-associated pneumonia/event (intubation >2 days)

— SSI — surgical site infection (within 30 days, or 90 days if implant)

— New fever, leukocytosis, hypotension, or altered mentation after hospital day 2

— Worsening trajectory in a patient previously improving — "the patient who turned the corner the wrong way"

— Purulent drainage at line, wound, or insertion site

— New oxygen requirement or infiltrate in an intubated patient

Board pearl: On Step 3, when a stem describes a hospital quality-improvement project to reduce CLABSI/CAUTI/VAP/SSI, the answer is almost always implement a checklist-driven bundle with daily review of necessity, not a new antibiotic or technology. Process change > product change.

Step 3 management: Any febrile inpatient after day 2 → simultaneously evaluate lines, lungs, urine, wound, and stool before reflexively broadening antibiotics.

Definition: Healthcare-associated infections (HAIs) are infections acquired ≥48 hours after hospital admission, within 30 days of a procedure, or within 90 days of implant placement, and not present/incubating on admission.

Big four HAIs targeted by CMS and CDC bundles:

Also bundle-targeted: C. difficile infection (CDI), MRSA bacteremia, multidrug-resistant organism (MDRO) transmission.

When to suspect HAI in a hospitalized patient:

Epidemiologic burden: ~1 in 31 inpatients has an HAI on any given day; HAIs cause ~99,000 US deaths/year and are a CMS never-event category for nonpayment (CLABSI, CAUTI, certain SSIs).

Bundle philosophy: A "bundle" is 3–5 evidence-based interventions applied together, with all-or-none compliance measurement. Partial adherence ≈ no benefit. Bundles work via standardization, not novelty.

Presentation Patterns and Key History

— Fever or rigors temporally linked to line flushing ("chills when the nurse flushed the PICC")

— Erythema, tenderness, or purulence at exit site (though often absent)

— Persistent bacteremia >72h despite appropriate antibiotics → think endovascular source

— Organisms: coagulase-negative staph, S. aureus, Enterococcus, gram-negatives, Candida (TPN, femoral lines)

— Often subtle: new delirium, low-grade fever, suprapubic discomfort

— Asymptomatic bacteriuria in a catheterized patient is NOT CAUTI and should not be treated (except pregnancy, pre-urologic procedure)

— Pyuria alone is insufficient — symptoms required

— New/worsening infiltrate + fever + purulent secretions + ↑FiO₂ or PEEP requirement after 48h of intubation

— Early-onset (<5 days): community-type organisms; late-onset (≥5 days): MRSA, Pseudomonas, Acinetobacter, ESBL gram-negatives

— Superficial (skin/subcutaneous): erythema, drainage within 30 days

— Deep (fascia/muscle): wound dehiscence, deep abscess

— Organ/space: intra-abdominal abscess, mediastinitis, prosthetic joint infection — up to 90 days post-implant

— ≥3 unformed stools/24h + recent antibiotics (especially fluoroquinolones, clindamycin, cephalosporins, carbapenems)

— Toxic megacolon, ileus, leukocytosis >15k = severe disease

Key distinction: Colonization vs. infection is the single most-tested concept. A positive urine culture in an asymptomatic Foley patient is colonization — treating it drives resistance and is a Step 3 safety wrong-answer. Same for tracheal aspirate growth without clinical VAP criteria, and skin-flora growth from a single blood culture without clinical signs.

Board pearl: Always ask for time of onset relative to admission, device insertion, or surgery — it anchors which bundle failed and which organism is likely.

CLABSI presentation:

CAUTI presentation:

VAP/VAE presentation:

SSI presentation:

CDI presentation:

Physical Exam Findings and Bedside Assessment

— qSOFA: RR ≥22, SBP ≤100, altered mental status (≥2 = high risk)

— Lactate, MAP, capillary refill, mottling

— Inspect every line daily — exit site for erythema, induration, purulence, tunnel tenderness

— Palpate along tunneled catheter tract — tenderness suggests tunnel infection requiring removal, not salvage

— Check dressing integrity, date, and necessity ("Does this patient still need central access?")

— Suprapubic tenderness, costovertebral angle tenderness

— Inspect catheter: dependent drainage, no kinks, bag below bladder, secured to thigh

— Ask: is the Foley still indicated? Acceptable indications: acute retention, accurate I/O in critical illness, perioperative <24h, sacral wound with incontinence, comfort care

— New rhonchi, asymmetric breath sounds, purulent endotracheal secretions

— Head-of-bed angle — should be 30–45° (a bundle element you can verify at the bedside)

— Erythema >2 cm beyond incision, fluctuance, dehiscence, drainage

— Stitch abscess vs. true SSI — superficial stitch reaction resolves with suture removal

— MAP <65 despite 30 mL/kg crystalloid → vasopressors, ICU

— Rising lactate, oliguria, mottling

CCS pearl: On CCS cases, physical exam of lines and wounds is a billable, scoreable action. Order "examine central line site" and "examine surgical wound" explicitly — and remove the Foley/central line as a discrete order when no longer indicated. The simulator rewards device removal as a quality action.

Step 3 management: Daily bedside question for every device → "Why is this still in?" If no answer, remove it.

General sepsis screen in every suspected HAI:

Line exam (CLABSI):

Urinary exam (CAUTI):

Pulmonary exam (VAP):

Surgical wound exam (SSI):

Hemodynamic red flags requiring escalation:

Diagnostic Workup — Initial Labs, Cultures, and Imaging

— CBC with differential, CMP, lactate, procalcitonin (trend more useful than single value)

— Blood cultures × 2 sets from separate sites before antibiotics — peripheral + line if CLABSI suspected (paired cultures with differential time to positivity >2h from line suggests line source)

— Urinalysis with microscopy + urine culture (only if symptomatic or catheter exchange)

— CXR for any respiratory symptom or unexplained fever

— Paired blood cultures (peripheral + each lumen)

— Do not routinely culture catheter tips unless line removed for suspected infection

— TTE if S. aureus, Candida, enterococcal bacteremia, or persistent bacteremia

— Replace catheter if in place >2 weeks, then culture from new catheter

— UA showing pyuria + symptoms + ≥10³ CFU/mL (catheterized) = CAUTI

— Lower respiratory sample: endotracheal aspirate (semi-quantitative) or BAL (quantitative ≥10⁴ CFU/mL)

— CXR — new/progressive infiltrate

— Avoid sputum Gram stain alone for diagnosis

— Wound culture from deep tissue or aspirate, not superficial swab

— CT for deep/organ-space infection (abscess, anastomotic leak)

— Two-step algorithm: GDH antigen + toxin EIA, or NAAT + toxin EIA

— Do not test formed stool or repeat testing as "test of cure"

Board pearl: Procalcitonin trends guide antibiotic de-escalation, not initial diagnosis. A falling procalcitonin supports stopping antibiotics; a single elevated value cannot rule in or rule out HAI.

Key distinction: Asymptomatic bacteriuria vs CAUTI — both have positive cultures; only CAUTI has symptoms. Treating ASB in non-pregnant, non-pre-procedural patients is a patient-safety wrong answer.

Universal initial workup for suspected HAI:

CLABSI-specific:

CAUTI-specific:

VAP-specific:

SSI-specific:

CDI-specific:

Diagnostic Workup — Advanced and Confirmatory Studies

— TTE first, then TEE if TTE negative but suspicion remains for endocarditis

— Mandatory TEE indications: S. aureus bacteremia, prosthetic valve, persistent bacteremia >72h on therapy, embolic phenomena

— Abdominal/pelvic CT with contrast for suspected intra-abdominal abscess, organ-space SSI, or unexplained sepsis without source

— Chest CT for complicated VAP (empyema, abscess, necrotizing pneumonia)

— Look for retained surgical hardware, anastomotic dehiscence, collections

— Drainable collection? IR-guided drainage required — antibiotics alone insufficient

— Necrotic tissue? Surgical debridement

— Infected hardware? Removal usually needed for cure

— MALDI-TOF and rapid PCR panels on positive blood cultures shorten time to organism ID by 24–48h → enable earlier targeted therapy and antibiotic stewardship

— Respiratory multiplex PCR (viral + atypical) for VAP differential

— Always request MIC for S. aureus (vancomycin MIC ≥2 → consider alternative), Pseudomonas, Enterococcus

— ESBL/CRE screening for gram-negative bacteremia

— MRSA nares PCR — high negative predictive value (~99%) for MRSA pneumonia; negative result supports de-escalating empiric vancomycin in VAP

— Active MRSA/VRE surveillance on ICU admission per institutional policy

Step 3 management: S. aureus bacteremia is a mandatory ID consult item — associated with reduced mortality, improved adherence to TEE, repeat blood cultures, and appropriate duration (minimum 14 days from first negative culture for uncomplicated; 4–6 weeks for complicated/endocarditis).

Board pearl: "Source control" is the high-yield phrase — undrained abscess + appropriate antibiotics = treatment failure. The exam tests whether you'll order the drainage, not just escalate antibiotics.

Echocardiography for bloodstream infection:

CT imaging:

Source control assessment:

Molecular and rapid diagnostics:

Susceptibility testing:

Surveillance cultures and screening:

Risk Stratification and Bundle-Based Management Logic

— Hand hygiene before insertion

— Maximal sterile barrier precautions (cap, mask, sterile gown, gloves, full body drape)

— Chlorhexidine skin antisepsis (>0.5% with alcohol; allow to dry)

— Optimal site selection — subclavian preferred over internal jugular over femoral for infection risk (balance against pneumothorax risk)

— Daily review of line necessity with prompt removal

— Insert only for appropriate indications

— Aseptic insertion, closed drainage system

— Secure catheter, keep bag below bladder, no dependent loops

— Daily review and prompt removal — nurse-driven removal protocols reduce CAUTI ~50%

— Avoid routine bladder irrigation and antimicrobial-coated catheters as primary strategy

— Head of bed 30–45°

— Daily sedation interruption (spontaneous awakening trial, SAT)

— Daily spontaneous breathing trial (SBT) to assess extubation readiness

— DVT prophylaxis

— Stress ulcer prophylaxis (re-evaluate daily — overuse increases pneumonia/CDI)

— Oral care with chlorhexidine (controversial; some institutions removing due to mortality signal)

— Subglottic suctioning ETT for anticipated intubation >48h

— Appropriate preoperative antibiotic within 60 min of incision (120 min for vancomycin/fluoroquinolones); redose for long cases

— Normothermia, normoglycemia (<180–200 mg/dL perioperatively)

— Chlorhexidine-alcohol skin prep

— Hair clipping (not shaving)

— Discontinue prophylactic antibiotics within 24h of surgery end (48h for cardiac)

Board pearl: Bundles are scored all-or-none. The Step 3 QI answer is almost always "implement checklist with daily audit and feedback," not adding a single new intervention.

CLABSI prevention bundle (CDC/IHI "Central Line Bundle"):

CAUTI prevention bundle:

VAP/VAE prevention bundle ("Wake up and breathe"):

SSI prevention bundle:

Pharmacotherapy — Empiric and Targeted Regimens

— Vancomycin (MRSA coverage) + antipseudomonal beta-lactam (cefepime, pip-tazo, or meropenem) for septic/ICU patients

— Add echinocandin (micafungin) if: TPN, prolonged broad-spectrum antibiotics, femoral line, hematologic malignancy, Candida colonization at multiple sites

— De-escalate within 48–72h based on cultures

— Mild: ceftriaxone or ertapenem

— Severe/septic: cefepime or pip-tazo; add vancomycin only if enterococcal risk

— Adjust to local resistance — ESBL prevalence drives carbapenem use

— Duration: 7 days if prompt response, 10–14 days if delayed

— ≥1 MDR risk factor (IV antibiotics in prior 90 days, septic shock, ARDS, ≥5 hospital days, RRT): vancomycin OR linezolid + antipseudomonal beta-lactam ± second antipseudomonal

— Otherwise: single antipseudomonal agent (e.g., pip-tazo or cefepime)

— Duration: 7 days for most VAP (shorter equals longer in outcomes, less resistance)

— Superficial: cephalexin or TMP-SMX (MRSA) ± clindamycin

— Deep/organ-space: vancomycin + pip-tazo or carbapenem; tailor by site (GI, GU, gyn)

— Source control first — drainage, debridement

— Initial episode or recurrence: fidaxomicin 200 mg BID × 10 days (preferred) or oral vancomycin 125 mg QID × 10 days

— Fulminant (ileus, megacolon, shock): oral/NG vancomycin 500 mg QID + IV metronidazole ± rectal vancomycin; surgical consult

— Multiple recurrences: fidaxomicin, vancomycin taper-pulse, or fecal microbiota transplant

— Metronidazole is no longer first-line for initial CDI

Step 3 management: De-escalate within 48–72h based on culture + clinical trajectory. Antibiotic stewardship — narrowing therapy and shortening duration — is itself a bundle element that reduces CDI and resistance.

Empiric therapy depends on suspected source, local antibiogram, prior cultures, and severity:

CLABSI empiric:

CAUTI empiric:

VAP empiric:

SSI empiric:

CDI treatment (2021 IDSA update):

Procedures and Source Control

— Remove the line for: S. aureus, Pseudomonas, Candida, mycobacteria, persistent bacteremia >72h, septic shock, tunnel infection, septic thrombophlebitis, endocarditis

— Line salvage with antibiotic lock therapy may be considered for: coagulase-negative staph, enterococcus, gram-negatives without complication, in patients with limited vascular access (e.g., hemodialysis)

— Replace at a new site, not over a guidewire, for infection

— Remove catheter if no longer indicated

— Exchange catheter if must remain — biofilm harbors organisms

— Relieve obstruction (stones, BPH) — urology consult

— Bronchoscopy for mucus plugging or persistent atelectasis

— Drain empyema (thoracostomy tube ± fibrinolytics or VATS)

— Open and drain superficial SSI; pack and dress

— Deep SSI: return to OR for debridement

— Organ/space SSI: IR or surgical drainage of abscess; manage anastomotic leak; remove infected mesh/hardware when feasible

— Discontinue inciting antibiotics when possible

— Subtotal colectomy or diverting loop ileostomy with vancomycin lavage for fulminant disease with toxic megacolon, perforation, or refractory shock

— Antimicrobial-impregnated CVCs (chlorhexidine/silver sulfadiazine or minocycline/rifampin) when CLABSI rates remain high despite bundle compliance

— Chlorhexidine bathing in ICU patients to reduce MDRO transmission and CLABSI

CCS pearl: On CCS, "remove central venous catheter" and "remove Foley catheter" are discrete, scorable orders. Combined with "infectious disease consultation" for S. aureus bacteremia, these are easy points often missed.

Source control is non-negotiable: Without it, antibiotics will fail. Source control beats antibiotic optimization on the exam.

CLABSI source control — line removal:

CAUTI source control:

VAP source control:

SSI source control:

CDI source control:

Adjunct procedural prevention:

Special Populations — Elderly and Renal/Hepatic Impairment

— Often present atypically: delirium, falls, anorexia, or hypothermia rather than fever and leukocytosis

— Functional decline + new confusion in a catheterized older adult → evaluate for CAUTI but don't reflexively treat asymptomatic bacteriuria even with delirium unless no other source

— Polypharmacy increases CDI risk (PPIs, recent antibiotics, opioids slow gut motility)

— Higher baseline MDRO colonization from nursing facilities

— Vancomycin: AUC-guided dosing (target 400–600 mg·h/L); trough 15–20 mg/L for serious infection if AUC unavailable; nephrotoxicity risk with concurrent pip-tazo (consider cefepime instead)

— Pip-tazo, cefepime, meropenem: dose-adjust for CrCl; cefepime neurotoxicity (encephalopathy, myoclonus, nonconvulsive status) in renal impairment — recognize and reduce dose

— Aminoglycosides: avoid when possible; if used, once-daily dosing with levels

— Daptomycin: every 48h if CrCl <30

— Tigecycline, ceftriaxone, nafcillin, linezolid: caution

— Linezolid → thrombocytopenia, serotonin syndrome with SSRIs, lactic acidosis with prolonged use (>14 days)

— Highest CLABSI risk population — tunneled HD catheters are major reservoirs

— Empiric vancomycin + gram-negative coverage; dose vancomycin after dialysis

— Strong push to transition to AV fistula/graft (Fistula First initiative)

— Avoid IM injections, femoral line attempts; subclavian risks pneumothorax — use US-guided IJ as compromise

Board pearl: Vancomycin + piperacillin-tazobactam (VPT) AKI — well-documented synergistic nephrotoxicity. In a patient with rising creatinine on VPT, swap pip-tazo for cefepime or meropenem; this is a high-yield Step 3 stewardship/safety question.

Step 3 management: Re-dose antibiotics with every renal function change; pharmacy consult is a legitimate, scoreable CCS action.

Elderly inpatients:

Renal impairment dosing adjustments:

Hepatic impairment:

Dialysis patients:

Anticoagulated patients:

Special Populations — Pregnancy, Pediatrics, Immunocompromised, and Surgical Patients

— Treat asymptomatic bacteriuria (exception to the general rule) — untreated → pyelonephritis, preterm labor, low birth weight

— Safe agents: penicillins, cephalosporins, azithromycin, clindamycin, nitrofurantoin (avoid at term and <12 weeks), fosfomycin (single dose for cystitis)

— Avoid: fluoroquinolones (cartilage), tetracyclines (teeth/bone), TMP-SMX (first trimester — neural tube; third trimester — kernicterus), aminoglycosides (ototoxicity)

— SSI prevention in C-section: cefazolin within 60 min before incision (not after cord clamp); add azithromycin for unscheduled/laboring C-section

— Neonatal CLABSI: coagulase-negative staph predominates; Candida in VLBW

— Avoid fluoroquinolones (with exceptions), tetracyclines <8 years

— Pediatric VAP bundles emphasize oral care, HOB elevation, cuff pressure

— Lower threshold for empiric broad-spectrum coverage

— Febrile neutropenia (ANC <500): cefepime, pip-tazo, or meropenem; add vancomycin for line infection, MRSA risk, hemodynamic instability, mucositis, skin/soft tissue

— Consider empiric antifungals after 4–7 days of persistent neutropenic fever

— Pneumocystis, CMV, atypical mycobacteria in transplant recipients

— Preoperative MRSA decolonization (nasal mupirocin + chlorhexidine bathing) for cardiac and orthopedic implant surgery

— Glycemic control (<180–200 mg/dL perioperatively) reduces SSI even in non-diabetics

— Normothermia (>36°C) — active warming reduces SSI, blood loss, cardiac events

— Smoking cessation ≥4 weeks preop reduces wound complications

Key distinction: Asymptomatic bacteriuria treatment indications — pregnancy and pre-urologic procedure with mucosal trauma. Every other adult: do not treat. This is one of the most frequently tested patient-safety pearls on Step 3.

Pregnancy:

Pediatrics:

Immunocompromised (neutropenia, transplant, HIV):

Surgical patients:

Complications and Adverse Outcomes

— Septic thrombophlebitis — persistent bacteremia, palpable cord, thrombus on imaging → line removal, anticoagulation, prolonged antibiotics (4–6 weeks)

— Endocarditis — S. aureus, enterococci, Candida; requires TEE, 4–6 weeks IV therapy, possible valve surgery

— Metastatic infection — septic arthritis, vertebral osteomyelitis, epidural abscess, splenic/renal abscess — especially with S. aureus

— Septic pulmonary emboli from right-sided endocarditis or septic thrombophlebitis

— Pyelonephritis, perinephric abscess, urosepsis

— Catheter-related strictures, bladder neck trauma, hematuria

— Fournier gangrene in diabetics — surgical emergency

— Empyema, lung abscess, necrotizing pneumonia (S. aureus, Klebsiella)

— Prolonged ventilation, tracheostomy, ICU delirium, post-ICU syndrome

— Mortality 20–50%

— Wound dehiscence, fistula, anastomotic leak

— Prosthetic infection — joints, mesh, vascular grafts — often requires removal

— Sepsis, secondary CDI from prolonged antibiotics

— Toxic megacolon (>6 cm), perforation, peritonitis, septic shock

— Recurrence (~20% after first episode, ~40–60% after second)

— Post-infectious IBS

— C. difficile superinfection

— Selection of MDROs: VRE, ESBL, CRE, MRSA, MDR Pseudomonas

— AKI (vancomycin, aminoglycosides, contrast)

— QT prolongation (fluoroquinolones, macrolides, linezolid)

— Hypersensitivity, drug fever, DRESS

— Cytopenias (linezolid → thrombocytopenia)

Board pearl: Persistent bacteremia >72h on appropriate antibiotics = search for source you missed — endocarditis, endovascular infection, undrained abscess, retained hardware, septic thrombophlebitis. Don't just escalate antibiotics; find and control the source.

CLABSI complications:

CAUTI complications:

VAP complications:

SSI complications:

CDI complications:

Antibiotic-related complications across all HAIs:

When to Escalate Care — ICU, Consult, and Inpatient Triage

— Septic shock (MAP <65 despite fluids → vasopressors)

— Respiratory failure requiring intubation or NIV with rising work of breathing

— Rising lactate >2 with hemodynamic instability

— Multi-organ dysfunction (AKI, coagulopathy, encephalopathy)

— Fulminant CDI (ileus, megacolon, shock)

— Infectious disease: S. aureus bacteremia (mandatory — improves outcomes), candidemia, endocarditis, CRE/MDR infections, OPAT planning, complex line salvage decisions, recurrent CDI

— Surgery: source control for SSI, organ-space infection, fulminant CDI (colectomy decision), necrotizing soft tissue infection

— Interventional radiology: percutaneous drainage of abscess

— Cardiothoracic surgery: valve replacement for endocarditis with HF, abscess, embolic events, or refractory infection

— Stewardship pharmacist: complex dosing, de-escalation, OPAT setup

— RR <8 or >30, SBP <90, HR <40 or >130, SpO₂ <90%, acute mental status change

— Empower nurses and families to activate (patient-safety culture)

— Hemodynamically stable, off vasopressors, lactate clearing, source controlled → step-down

— Stable hardware infections on IV antibiotics → consider OPAT with PICC + infusion center follow-up

— Identify IV-to-PO conversion candidates early (tolerating PO, hemodynamically stable, source controlled, susceptible to oral agent with adequate bioavailability — fluoroquinolones, linezolid, metronidazole, TMP-SMX)

— OPAT setup requires home infusion, weekly labs (CBC, BMP, drug levels), ID follow-up

Step 3 management: Sepsis Hour-1 Bundle — measure lactate, blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour, 30 mL/kg crystalloid for hypotension or lactate ≥4, vasopressors if MAP <65 after fluids. This is reflexively tested.

ICU transfer criteria:

Consult triggers:

Rapid response activation criteria (most institutions):

Step-down vs. ward considerations:

Transition planning during admission:

Key Differentials — Same-Category (Other Infections)

— All catheters and devices: central line, Foley, ET tube, surgical drains, chest tubes, epidurals, hardware

— Wound and surgical sites

— GI tract: CDI, cholecystitis (especially TPN/fasting → acalculous), abscess

— Lungs: VAP, aspiration pneumonia, empyema

— Urinary tract: CAUTI, prostatitis, perinephric abscess

— Bloodstream: primary bacteremia, endocarditis

— Community-acquired pneumonia present on admission vs HAP/VAP — timing matters for organism coverage and reporting

— Recurrent UTI in chronically catheterized vs new CAUTI

— Pre-existing osteomyelitis vs hospital-acquired hardware infection

— Often >5 days into therapy, relative bradycardia, eosinophilia, otherwise well-appearing

— Common offenders: beta-lactams, sulfa, phenytoin, allopurinol

— Resolves within 48–72h of stopping the drug

— Febrile non-hemolytic (most common), TRALI, TACO, bacterial contamination

— Fever during or shortly after transfusion

— Pneumonitis: chemical inflammation, often self-limited, antibiotics not initially indicated

— Pneumonia: clinical worsening 48–72h after aspiration → treat

— Often blamed for postop fever but evidence is weak; rule out true infection rather than dismissing

Key distinction: HAP vs VAP — both are hospital-acquired pneumonia ≥48h after admission; VAP requires intubation ≥48h. Both empiric regimens are similar, but VAP carries higher MDR risk and worse outcomes.

Board pearl: Postop day 1 fever → usually atelectasis or inflammatory response; postop day 3–5 → UTI, pneumonia; day 5–7 → SSI, DVT; >7 days → deep SSI, abscess, drug fever, CDI ("Wind, Water, Wound, Walking, Wonder drugs").

Fever in a hospitalized patient — don't anchor on first device:

Non-HAI infections to distinguish:

Drug fever:

Transfusion reactions:

Aspiration pneumonitis vs aspiration pneumonia:

Atelectasis:

Tropical/travel-related infections in returning travelers admitted for other reasons (malaria, dengue, typhoid)

Key Differentials — Other-Category (Non-Infectious Causes of Fever)

— DVT/PE can cause low-grade fever, tachycardia, leukocytosis

— Always on differential for postop fever — order duplex or CTPA when clinically suspected

— Drug fever, DRESS (eosinophilia, rash, organ involvement, often 2–8 weeks in)

— Neuroleptic malignant syndrome, serotonin syndrome

— Malignant hyperthermia (postop, succinylcholine/volatile anesthetics)

— Thyroid storm, adrenal crisis (especially with steroid taper or stress)

— Pheochromocytoma crisis

— Gout/pseudogout flare (common in hospitalized patients)

— Lupus flare, vasculitis

— Acute pancreatitis (postop, post-ERCP)

— Tumor fever (lymphoma, renal cell, hepatocellular)

— Transfusion reactions

— Hematoma resorption

— Myocardial infarction (especially perioperative)

— Pericarditis (Dressler, post-cardiotomy)

— Aortic dissection

— Central fever (stroke, intracranial hemorrhage, traumatic brain injury) — diagnosis of exclusion

— Seizures

— Heat stroke, malignant hyperthermia

— Withdrawal syndromes (alcohol, benzodiazepines, opioids) — fever, tachycardia, agitation

— Phlebitis at peripheral IV sites without infection

Step 3 management: Postoperative fever workup is directed by timing and exam, not reflex pan-culture. POD 1 walking ambulation > antibiotics. Reflex pan-culture without clinical correlation is wasteful, drives false positives, and is a stewardship/safety wrong answer.

Board pearl: Calcineurin inhibitors and steroids mask fever in transplant patients — a low-grade temp or unexplained tachycardia may be the only sign of serious infection.

Venous thromboembolism:

Drug reactions:

Endocrine:

Inflammatory/autoimmune:

Hematologic/oncologic:

Cardiovascular:

Neurologic:

Environmental:

Iatrogenic:

Secondary Prevention, Discharge Planning, and Long-Term Plan

— Most HAIs: shortest effective course (VAP 7d, CAUTI 7d, uncomplicated CLABSI 7–14d, CDI 10d)

— Transition to oral when: hemodynamically stable, tolerating PO, source controlled, organism susceptible to bioavailable oral agent

— Highly bioavailable oral agents: fluoroquinolones, linezolid, metronidazole, TMP-SMX, fluconazole, doxycycline

— Indicated for: endocarditis, osteomyelitis, deep abscess, complicated bacteremia requiring prolonged IV therapy

— Requires PICC, home infusion, weekly labs (CBC, BMP, drug levels), ID follow-up

— Document end date and stewardship review

— Avoid sending patients home with Foleys unless absolutely indicated; condom catheter or intermittent straight cath preferred

— Tunneled lines only if ongoing therapy mandates; arrange line removal date

— Recurrent MRSA SSTI: nasal mupirocin + chlorhexidine bathing × 5–10 days, household decolonization, hygiene measures

— Pre-cardiac/orthopedic surgery: nasal mupirocin + chlorhexidine 5 days preop

— Avoid unnecessary antibiotics and PPIs

— Consider bezlotoxumab (monoclonal antibody) for high-risk patients during treatment of recurrent CDI

— FMT for ≥2 recurrences

— Influenza (seasonal), pneumococcal (PCV20 or PCV15+PPSV23), COVID-19, RSV (≥60), Tdap, zoster (≥50)

— Update during hospitalization — captive audience, missed otherwise

— Hand hygiene, wound care, signs of recurrence, when to seek care

— Medication reconciliation at discharge with teach-back

Step 3 management: Medication reconciliation at every transition of care (admission, transfer, discharge) is a Joint Commission National Patient Safety Goal and the single biggest preventable source of post-discharge harm.

Antibiotic duration and IV-to-PO transition:

OPAT (outpatient parenteral antibiotic therapy):

Device decisions at discharge:

Decolonization for recurrent infections:

CDI recurrence prevention:

Vaccinations before discharge:

Patient education:

Follow-Up, Monitoring Parameters, and Counseling

— PCP visit within 7–14 days for any hospitalization (CMS Transitions of Care quality metric); within 7 days for high-risk (sepsis, complex infection)

— ID follow-up at 1–2 weeks for complicated bacteremia, endocarditis, OPAT patients

— Surgical follow-up at 1–2 weeks for SSI; sooner for drainage in place

— Weekly CBC, BMP, LFTs for OPAT

— Vancomycin: trough or AUC; baseline and at least weekly renal function

— Linezolid >14 days: weekly CBC (thrombocytopenia), monitor for neuropathy, serotonin syndrome

— Aminoglycosides: peak/trough, audiology baseline for prolonged use

— Daptomycin: weekly CPK

— Fever defervescence within 72h

— Trending WBC, CRP, procalcitonin downward

— Repeat blood cultures at 48–72h for S. aureus, Candida, persistent fever

— Repeat imaging if not improving — undrained source?

— Not routinely indicated for most HAIs after clinical resolution

— No repeat C. diff testing after symptomatic improvement — molecular tests stay positive for weeks

— Repeat urine culture only for pregnancy or pre-procedural

— Post-sepsis syndrome: cognitive impairment, functional decline, depression, recurrent infections — screen at follow-up visits

— Post-ICU syndrome: PTSD, ICU-acquired weakness — refer to rehab

— Recurrent CDI risk persists 8–12 weeks — counsel on antibiotic avoidance

— Importance of completing antibiotic course (with caveat that shorter is often better — follow prescribed course)

— Hand hygiene at home, especially during CDI recovery

— Probiotics: routine use not recommended for CDI prevention by IDSA

Board pearl: Bezlotoxumab reduces CDI recurrence by ~10 absolute percentage points in high-risk patients (age ≥65, severe CDI, immunocompromised, prior CDI) — given as a one-time IV infusion alongside standard antibiotic therapy.

Post-discharge follow-up cadence:

Lab monitoring during therapy:

Clinical response markers:

Test of cure:

Long-term complications surveillance:

Counseling content:

Ethical, Legal, and Patient Safety Considerations

— CMS reports HAI rates publicly (Hospital Compare); poor performers face payment penalties under the Hospital-Acquired Condition Reduction Program

— CLABSI, CAUTI, certain SSIs, MRSA bacteremia, CDI are reportable to NHSN

— "Never events" (selected HAIs after elective procedures) → CMS nonpayment for incremental costs

— Ethical and legal obligation to disclose preventable HAIs to patients/families

— Most states have apology laws protecting expressions of regret from use in litigation

— Disclosure should be timely, factual, accompanied by ongoing care plan and system response

— Central line, Foley, intubation, surgery — include infection risk in consent discussion

— Document discussion of alternatives (e.g., midline vs central line, intermittent cath vs Foley)

— Specific MDROs (CRE, Candida auris, novel resistance) reportable to state/local health departments

— Outbreak clusters: prompt infection prevention notification

— Discharge summary to PCP within 48 hours, including pending cultures, antibiotic stop date, follow-up labs

— Pending test results at discharge are a leading source of post-discharge harm — explicit handoff protocol required

— Medication reconciliation accuracy — antibiotic duration errors common

— HAIs → RCA to identify system failures (process, equipment, staffing, training) rather than individual blame

— Just culture distinguishes human error, at-risk behavior, and reckless conduct — supports reporting and learning

— Direct observation, video monitoring, peer auditing; compliance ~50% baseline

— The single most effective HAI prevention intervention, repeatedly underperformed

— Avoid harm to future patients through resistance — population-level ethics

— Joint Commission requires stewardship programs in all hospitals

Step 3 management: When a CCS or vignette presents a near-miss or sentinel event, the correct response is disclosure to patient + report to safety system + RCA, not concealment or individual punishment.

Public reporting and value-based purchasing:

Disclosure of harm:

Informed consent for device placement:

Mandatory reporting:

Transition-of-care safety:

Just culture and root cause analysis:

Hand hygiene compliance:

Antibiotic stewardship as ethical obligation:

High-Yield Associations and Rapid-Fire Clinical Facts

— TPN, femoral line → Candida

— Hemodialysis catheter → S. aureus

— Coagulase-negative staph → most common, often contaminant; need ≥2 positive cultures to call it real

— Clean (skin, breast, hernia): S. aureus, CoNS

— Clean-contaminated (GI, GU, gyn): polymicrobial — enterics + anaerobes

— Cardiac surgery sternal: MSSA, MRSA, CoNS

— Successful CLABSI programs achieve >90% bundle compliance and reduce rates >50%

— Keystone ICU Project (Michigan) reduced median CLABSI rate to zero in many ICUs

Board pearl: Soap and water — not alcohol gel — for C. difficile and after caring for any patient with diarrhea. Alcohol does not kill spores. This is a perennially tested point.

Key distinction: Surveillance definitions vs clinical diagnosis — a patient may meet NHSN CLABSI criteria but have an alternative clinical explanation; conversely, you may treat clinically without meeting surveillance criteria.

CLABSI organisms by context:

CAUTI: E. coli most common; Pseudomonas, Enterococcus, Candida with prolonged catheterization

VAP early (<5 days): Strep pneumoniae, H. influenzae, MSSA, sensitive enterics

VAP late (≥5 days): Pseudomonas, Acinetobacter, MRSA, ESBL/CRE

SSI:

CDI risk factors: antibiotics (clindamycin, fluoroquinolones, cephalosporins, carbapenems), PPI, age >65, recent hospitalization, IBD, immunocompromise

Bundle compliance benchmarks:

Hand hygiene: alcohol-based rub preferred except for C. difficile (use soap and water — spores resist alcohol) and visibly soiled hands

Contact precautions: MRSA, VRE, CRE, CDI (gown + gloves; private room)

Droplet precautions: influenza, pertussis, N. meningitidis, mumps (surgical mask)

Airborne precautions: TB, measles, varicella, disseminated zoster, COVID-19 during aerosol-generating procedures (N95 + negative-pressure room)

Surveillance definitions matter: NHSN definitions for HAIs are surveillance, not clinical, definitions — used for benchmarking

PPE donning/doffing: doffing is when contamination occurs — most errors are at removal

Board Question Stem Patterns

— "A hospital wants to reduce its CLABSI rate from X to Y. Which intervention is most likely to succeed?"

— Answer: implement evidence-based bundle with checklist + daily audit + feedback. Wrong answers: a single new product (antimicrobial dressing alone), staff retraining alone, punitive measures.

— Catheterized older adult with positive urine culture, no fever, no localizing symptoms, possible delirium

— Answer: Do not treat unless pregnant or pre-urologic procedure. Look for alternative cause of delirium.

— S. aureus bacteremia, blood cultures still positive at 72h

— Answer: TEE (look for endocarditis), remove line, ID consult, repeat cultures, look for metastatic foci

— Patient on VPT develops rising creatinine

— Answer: Switch pip-tazo to cefepime or meropenem; adjust vancomycin

— Day 1 = atelectasis/inflammatory; Day 3–5 = UTI, pneumonia; Day 5–7 = SSI, DVT; >7 = deep abscess, drug fever, CDI

— Patient with second CDI episode

— Answer: Fidaxomicin or vancomycin taper-pulse; consider bezlotoxumab; FMT for ≥2 recurrences

— Hospital reports 80% compliance with each individual bundle element

— Answer: Measure all-or-none compliance, which will be much lower; focus on simultaneous adherence

— Stem mentions caring for CDI patient → soap and water, not alcohol gel

— Stem describes Foley in place for "convenience"

— Answer: Remove the Foley; not an appropriate indication

— Answer: Cefazolin within 60 minutes before incision; discontinue within 24h postop

Step 3 management: When in doubt, the right answer involves device removal, source control, narrowing antibiotics, or systems-level prevention — rarely a fancier antibiotic.

Pattern 1 — The QI project:

Pattern 2 — The asymptomatic bacteriuria trap:

Pattern 3 — Persistent bacteremia:

Pattern 4 — Vancomycin + pip-tazo AKI:

Pattern 5 — Postoperative fever timing:

Pattern 6 — CDI recurrence:

Pattern 7 — Bundle compliance "all-or-none":

Pattern 8 — Hand hygiene with C. diff:

Pattern 9 — Foley necessity review:

Pattern 10 — Surgical antibiotic prophylaxis timing:

One-Line Recap

Healthcare-associated infections are largely preventable through disciplined, all-or-none adherence to evidence-based bundles for line, catheter, ventilator, and surgical site care — with daily review of device necessity, antimicrobial stewardship, and source control as the cornerstones of both prevention and treatment.

— CLABSI: hand hygiene, max sterile barriers, chlorhexidine prep, optimal site, daily necessity review

— CAUTI: appropriate indication only, aseptic insertion, closed system, dependent drainage, daily removal review

— VAP: HOB 30–45°, daily sedation interruption + SBT, DVT and stress ulcer prophylaxis, oral care

— SSI: preop antibiotic within 60 min, normothermia, glycemic control, chlorhexidine prep, hair clipping (not shaving), stop prophylaxis within 24h

— Empiric coverage based on local antibiogram and severity; de-escalate at 48–72h

— Shortest effective duration (VAP 7d, CAUTI 7d, CDI 10d, uncomplicated CLABSI 7–14d)

— IV-to-PO transition when hemodynamically stable and tolerating PO

— Do not treat asymptomatic bacteriuria (except pregnancy and pre-urologic procedure)

— Soap and water — not alcohol gel — for C. difficile

— "Why is this device still in?" — asked daily for every line, tube, drain, and catheter. If there is no defensible answer, remove it now.

Board pearl: The Step 3 HAI question almost never rewards a new antibiotic — it rewards process change, device removal, source control, and bundle adherence. Think systems, not pharmacology.

The Four Bundle Pillars:

The Three Stewardship Imperatives:

The Two Patient-Safety Non-Negotiables:

The One Universal Question: