Infections Acquired in Health Care Facilities¶
Chapter 147 | Part 5: Infectious Diseases
KEY CLINICAL POINTS¶
- Healthcare-associated infections (HAIs) affect at least 3% of hospitalized patients, with rising rates of multidrug-resistant infections during the COVID-19 pandemic.
- Prevention strategies include hand hygiene, environmental cleaning, and evidence-based bundles for device-related infections (e.g., chlorhexidine baths, aseptic techniques).
- C. difficile and Candida auris are critical pathogens requiring strict isolation precautions, sporicidal disinfectants, and targeted antimicrobial stewardship.
1. DEFINITION & OVERVIEW¶
Healthcare-associated infections (HAIs) are infections acquired in healthcare settings, including hospitals, long-term care facilities, and outpatient clinics. These infections are a major cause of morbidity and mortality, often linked to antimicrobial resistance. Key pathogens include multidrug-resistant organisms (MDROs), fungal infections (e.g., Candida species), and viral agents (e.g., norovirus).
Table 147-1: Evidence-Based Bundled Measures to Reduce Device-Related Infections¶
| Prevention Type | Key Measures |
|---|---|
| Surgical Site Infections | Prophylactic antibiotics within 1 hour pre-op, chlorhexidine antisepsis, positive pressure OR airflow |
| Ventilator-Associated Pneumonia | Elevate head of bed to 30–45°, daily chlorhexidine baths, aseptic respiratory equipment care |
| Catheter-Associated Urinary Tract Infections | Daily reevaluation of catheter necessity, aseptic insertion, minimize instrumentation |
| Catheter-Associated Bloodstream Infections | Chlorhexidine baths, daily hub scrubbing, disinfectant caps, maximum sterile barrier |
1.1 Healthcare-Associated Infections¶
HAIs occur in patients after admission or within 48–72 hours of hospitalization. They are classified as nosocomial infections and include surgical site infections, catheter-associated urinary tract infections (CAUTIs), ventilator-associated pneumonia (VAP), and bloodstream infections. Transmission occurs via contaminated surfaces, healthcare workers, or medical devices.
1.2 Rabies and Tetanus Prophylaxis¶
Rabies prophylaxis includes rabies immune globulin and vaccine, while tetanus requires booster doses for patients with prior immunization. Elevation of injured sites and immobilization reduce infection risk.
2. EPIDEMIOLOGY¶
HAIs affect ~3% of hospitalized patients globally. Rates declined before the COVID-19 pandemic but rose during the pandemic due to infection control challenges. Multidrug-resistant organisms (MDROs) like MRSA, VRE, and carbapenem-resistant Enterobacterales (CRE) are increasingly prevalent. Risk factors include immunocompromise, prolonged hospitalization, and invasive devices.
Table 147-4: Estimated Risk of Bloodborne Pathogen Transmission from Percutaneous Injury¶
| Pathogen | Risk |
|---|---|
| Hepatitis B | 6–30% |
| Hepatitis C | 1–3% |
| HIV | 0.3% |
2.1 Incidence and Prevalence¶
HAIs are a leading cause of hospital-acquired morbidity and mortality. Post-surgical infections occur more frequently in emergency settings or with comorbidities like diabetes. Device-related infections (e.g., CAUTIs, CLABSIs) are common in ICU patients.
2.2 Risk Factors¶
Immunocompromised patients (e.g., neutropenia, diabetes), elderly, and those with indwelling devices (e.g., catheters, ventilators) are at highest risk. Poor hand hygiene and environmental contamination contribute to transmission.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
HAIs are caused by multidrug-resistant bacteria (e.g., MRSA, VRE, CRE), fungi (e.g., C. difficile, C. auris), and viruses (e.g., norovirus, influenza). Pathogenesis involves colonization of healthcare environments, transmission via contaminated surfaces or personnel, and immune compromise. MDROs thrive in hospital settings due to antibiotic pressure and poor infection control.
3.1 Multidrug-Resistant Bacteria¶
MDROs like MRSA, VRE, and CRE are driven by antibiotic misuse and poor hygiene. C. difficile spreads via spores, while C. auris is resistant to common disinfectants and persists on surfaces.
3.2 Fungal Infections¶
Candida species (especially C. auris) and Aspergillus are common in immunocompromised patients. C. auris is particularly challenging due to its resistance to antifungals and environmental persistence.
4. CLINICAL FEATURES¶
Symptoms vary by infection type: surgical site infections present with redness/pain, CAUTIs with dysuria, and VAP with fever and purulent sputum. C. difficile causes watery diarrhea, while C. auris may be asymptomatic or present with fever and rash. MDRO infections are often associated with prolonged hospital stays and higher mortality.
4.1 Common Presentations¶
Surgical site infections, CAUTIs, VAP, and bloodstream infections are the most common HAIs. C. difficile colitis ranges from mild diarrhea to toxic megacolon. C. auris infections may be asymptomatic or present with fever, rash, or sepsis.
4.2 Complications¶
MDRO infections increase mortality and healthcare costs. C. difficile can lead to pseudomembranous colitis, while C. auris may cause fungemia and septic shock.
5. DIFFERENTIAL DIAGNOSIS¶
Differential diagnoses include community-acquired infections (e.g., urinary tract infections, pneumonia) and non-infectious conditions (e.g., surgical complications). For C. difficile, differentiate from other causes of diarrhea (e.g., viral, bacterial). For C. auris, rule out other fungal infections and consider environmental contamination.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnostic tests include cultures (blood, urine, wound), PCR for C. difficile toxin, and molecular typing for outbreak detection. Urine cultures should be reserved for symptomatic patients. C. auris requires specialized testing (PCR, culture) due to resistance to standard disinfectants.
Table 147-2: Diagnostic Stewardship Examples¶
| Test | Stewardship Measures |
|---|---|
| Urine Culture | Educate clinicians on asymptomatic bacteriuria; avoid testing in asymptomatic patients |
| C. difficile Testing | Use toxin detection assays; avoid unnecessary testing in non-neutropenic patients |
| C. auris Testing | PCR and culture required; avoid standard disinfectants |
6.1 Laboratory Tests¶
Cultures for blood, urine, and wound specimens; C. difficile toxin assays; molecular diagnostics for MDROs. Urine cultures should be avoided in asymptomatic patients.
6.2 Imaging¶
Imaging (e.g., CT) may be used for abscesses or complications like empyema. Ultrasound guides catheter placement and detects device-related infections.
7. MANAGEMENT & TREATMENT¶
Treatment includes antimicrobial stewardship, isolation precautions, and device removal. For C. difficile, metronidazole or vancomycin; for C. auris, echinocandins. Prevention strategies include chlorhexidine baths, aseptic techniques, and environmental disinfection.
Table 147-3: Health Care Personnel Immunizations¶
| Vaccine | Eligibility | Recommendations |
|---|---|---|
| COVID-19 | All HCP | Per CDC recommendations |
| Influenza | All HCP | Annual vaccination |
| Vaccine | Eligibility | Recommendations |
|---|---|---|
| Hepatitis B | HCP without immunity | Two-dose or three-dose series |
| MMR | HCP without immunity | Two doses at 4-week intervals |
| Tdap | HCP without recent vaccination | Single dose, booster every 10 years |
7.1 Antimicrobial Therapy¶
Tailor antibiotics to culture results and resistance patterns. For MDROs, use carbapenems, vancomycin, or combination therapy. C. difficile requires metronidazole or vancomycin.
7.2 Infection Control¶
Contact precautions for C. difficile and C. auris; sporicidal disinfectants (e.g., bleach) for environmental cleaning. Universal precautions for bloodborne pathogens.
8. PROGNOSIS & COMPLICATIONS¶
Prognosis varies by pathogen and patient factors. MDRO infections are associated with higher mortality and prolonged hospitalization. C. difficile can lead to pseudomembranous colitis, while C. auris may cause fungemia and septic shock. Poor outcomes are linked to delayed diagnosis and treatment.
9. SPECIAL CONSIDERATIONS¶
Pregnancy, pediatrics, and elderly patients require tailored approaches. For example, C. difficile is more common in elderly patients, while C. auris is often seen in ICU patients. Vaccination of healthcare workers is critical to prevent transmission.
9.1 Pregnancy¶
Avoid certain antibiotics (e.g., tetracyclines) and use antifungals cautiously. C. difficile and C. auris require isolation to prevent vertical transmission.
9.2 Elderly Patients¶
Higher risk of C. difficile and C. auris infections due to immunosenescence and comorbidities. Frequent reevaluation of catheter necessity is essential.
10. KEY POINTS & CLINICAL PEARLS¶
- HAIs affect 3% of hospitalized patients, with rising MDRO rates during the pandemic.
- Chlorhexidine baths, aseptic techniques, and sporicidal disinfectants are critical for prevention.
- C. difficile and C. auris require strict isolation and specialized testing.
- Vaccination of healthcare workers is essential to prevent transmission of vaccine-preventable pathogens.