Infection Control & Nursing Care Comprehensive Study Notes

Chain of Infection

• Links (6-Link Model)
  1. Infectious Agent (Pathogen) – bacteria, viruses, fungi, protozoa, helminths, prions.
  2. Reservoir – animate (people, animals, insects, plants) & inanimate (soil, water, medical devices).
  3. Portal of Exit – sputum, emesis, stool, urine, blood, wound drainage, sweat.
  4. Mode of Transmission
     • Direct contact (skin-to-skin, kissing, sex).
     • Indirect/vehicle (fomites, food, water, blood).
     • Droplet (influenza, pertussis, COVID).
     • Airborne (measles, varicella, TB, COVID).
     • Vector (ticks—Lyme; mosquitoes—West Nile, Zika; rats—plague).
  5. Portal of Entry – respiratory tract, GI tract, GU tract, mucous membranes, skin breaks, placenta.
  6. Susceptible Host – burns, wounds, chronic disease, immunocompromise (HIV, chemo, steroids, transplant), extremes of age, malnutrition, stress, smokers, immobilized, invasive devices, hospitalized/LTC clients.
• Break any link → no infection.

Body Defenses

1. Physical & Chemical Barriers

• Skin & intact mucous membranes (moist, pink).
• Cilia, coughing, sneezing.
• Gastric acid (pH ≈ 1–5).
• Lysosomes in tears/saliva.
• Normal microbiota (gut, skin, mouth, vagina).

2. Inflammatory Response

1. Vascular phase – vasodilation, ↑ blood flow → redness & heat.
2. Plasma exudate – proteins & fluid → swelling & warmth.
3. Cellular phase (phagocytosis) – neutrophils, macrophages engulf debris; exudate may be serous, serosanguineous, purulent.
   • Local S/S = Redness Edema Heat Pain (± ↓ function).
   • Excessive response ⇒ SIRS (Systemic Inflammatory Response Syndrome).

3. Immune System

• Organs: bone marrow, thymus (T-cells), spleen, lymph nodes/vessels.
• Cells: leukocytes, antibodies (IgG, IgA, IgM, IgE, IgD), interferon.
• Immunity types
– Innate (genetic).
– Acquired • Active (disease or vaccine) • Passive (colostrum, IVIG).
• Herd Immunity – community protection once critical % immune (varies by disease).

From SIRS → Sepsis Continuum

Early cues: fever, chills, malaise, tachycardia, tachypnea, nausea/vomiting, ↓ urine, mental changes.

Management “Sepsis Bundle” (first hour)

1. Blood cultures ×2.
2. Broad-spectrum antibiotic (e.g., Zyvox) within 1 h.
3. Lactate, CBC-diff, CMP, coagulation.
4. Rapid IVF: 30\;mL/kg NS/LR.
5. O₂ to keep SpO₂ > 94\%.
6. Vasopressors if MAP < 65 after fluid.

Common Pathogens & Resistant Strains

• Staph aureus – MRSA (methicillin resistant)
• Enterococci – VRE (vancomycin resistant)
• Enterobacteriaceae – CRE (carbapenem resistant)
• E. coli – UTIs, urosepsis
• Pseudomonas – wounds, burns (blue-green, sweet odor)
• Clostridioides difficile – antibiotic-assoc. colitis

Key Drugs & Monitoring

Laboratory Reference Quick-List

• WBC 5–10\times10^3/µL
• Albumin 3.5–5.5\;g/dL
• Creatinine 0.5–1.5\;mg/dL
• BUN 8–20\;mg/dL
• Sodium 135–145\;mEq/L
• Potassium 3.5–5.0\;mEq/L
• ESR (Sed Rate) 0–20\;mm/h; > 40 suggests inflammation.

Medical vs Surgical Asepsis

• Medical (Clean) – hand hygiene, clean gloves, routine dressings, NG/PEG care, blood draw.
• Surgical (Sterile) – OR, labor & delivery, central/PICC insertion & dressing, catheter insertion/changes, trach suctioning (dominant sterile hand), lumbar puncture.

Precaution Categories

Catheter-Associated UTI (CAUTI) Prevention

• Justifiable Foley: urologic surgery, stage III/IV pressure injury, neurogenic retention after ≥2 failed straight caths, epidural anesthesia, strict ICU I/O, end-of-life comfort.
• Insert with sterile technique; secure to thigh; maintain closed drainage; keep bag below bladder; daily CHG/perineal care; review DAILY for removal.

Ventilator-Associated Pneumonia (VAP) Bundle

1. HOB ≥30^{\circ} (30–45^{\circ} when tube feeding).
2. Daily sedation vacation & readiness to extubate.
3. Stress ulcer & DVT prophylaxis.
4. Oral care q2–4 h with 0.12\% CHG; lip moisturizer.
5. Closed in-line suction; hyper-oxygenate before suctioning.

Gastrointestinal Infection Focus: C. difficile

• Risk: abx (cephalosporins, penicillins, clindamycin), PPI use, ≥65 yr, LTC stay.
• Dx: stool toxin assay/PCR.
• Tx: PO vancomycin 125 mg q6h ×10 d (or fidaxomicin). IV Flagyl only if ileus.
• Severe/recurrent: Fecal Microbiota Transplant (FMT) via colonoscopy/oral capsules.

Nursing Process Highlights

• Assessment – targeted S/S by system, cultures before antibiotics, trend VS & labs.
• Diagnosis – Risk for Infection, Knowledge Deficit, Fluid Volume Deficit, Acute Pain.
• Planning/Goals – Afebrile

Quick Teaching Points

• Finish all antibiotics; report severe diarrhea (>3 watery stools/day).
• Proper condom use to prevent STIs (HIV, HPV, gonorrhea, chlamydia, syphilis).
• Vaccines: flu annually; Tdap q10 yrs; COVID boosters per CDC; HPV (Gardasil) ages 9–26 (2–3-dose series).
• Hand hygiene: soap & water \ge20 s; alcohol sanitizer \ge70\% (not for C-diff).
• PPE don/doff order; N95 fit-test yearly with saccharin test.

Normal & Critical Values Cheat-Sheet

• Temp >100.4^{\circ}F (38 °C) or <96.8^{\circ}F (36 °C) → sepsis alert.
• Lactate >2 mmol/L concerning; >4 critical.
• MAP <65 mm Hg → initiate vasopressors.
• Urine specific gravity 1.005–1.030; concentrated >1.030 signals dehydration.

Ethical & Practical Considerations

• Balance autonomy vs institutional mandates for vaccines/PPE.
• Equitable resource allocation during outbreaks.
• Evidence-based protocols (e.g., Sepsis Campaign) tied to quality metrics & reimbursement.

“Bad Word” Checklist (Instructor Emphasis)

• Infection
• Sepsis
• Staph/MRSA
• C. diff
• Staph infections in joints
• Catheters & central lines as reservoirs.

Exam Tips

1. Know which infections use which Precaution category.
2. Memorize vancomycin & Flagyl nursing care.
3. Recognize early SIRS criteria; know sepsis labs (CBC-diff, CMP, cultures, lactate).
4. Understand justifiable Foley indications.
5. Albumin <3.5 g/dL → malnutrition risk → infection susceptibility.