Summary
Hospital-acquired infections (HAIs), also called health care-associated infections (HCAIs) and nosocomial infections, are infections contracted in a hospital or other health care facility that were not present or incubating at the time of admission. Symptoms and/or signs of an HAI typically manifest 48 hours or more after admission. HAIs are transmitted through patient exposure to health care workers, other patients, hospital equipment, or interventional procedures. The most common types of HAIs include intravascular catheter-related bloodstream infection (CRBSI), catheter-related urinary tract infection (CAUTI), hospital-acquired pneumonia, ventilator-associated pneumonia, surgical site infection (SSI), and Clostridioides difficile infection (CDI). The most common causative pathogens differ depending on the site of infection (e.g., gastrointestinal tract, urinary tract, lungs, skin). An increasing number of HAIs are caused by multidrug-resistant organisms (MDROs). Common MDROs include methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase-producing bacteria (ESBL).
This article provides an overview of the diagnosis and management of common HAIs. Prevention of nosocomial infections is covered separately.
See also “Intravascular catheter-related bloodstream infections,” “Device-related infections,” and “Bacteremia.”
Definitions
The following terms are often used interchangeably:
- Hospital-acquired infection (nosocomial infection): an infection acquired in a hospital or another inpatient health care facility that was not present or incubating at the time of admission [1]
- Health care-associated infection (HCAI): an infection acquired after receiving health care in any setting (including a hospital, long-term care facility, nursing home, ambulatory care clinic, home care, or surgical intervention) [2][3]
Etiology
Risk factors [4][5][6][7]
- Age > 70 years
-
Lengthy hospital stays; pathogen transmission can occur via:
- Medical staff (e.g., insufficient disinfection of hands, clothing)
- Contact surfaces (e.g., equipment, furniture)
- Contaminated indoor air (e.g., via droplets)
-
Iatrogenic causes
- Foreign bodies (e.g., catheters, intravenous catheters, endotracheal tubes) and invasive instruments
- Multiple interventional procedures (e.g., in patients with shock, major trauma, acute renal failure, coma)
- Mechanical ventilation
- Hemodialysis
- Recent antibiotic use
- Metabolic diseases (especially diabetes mellitus)
- Immunosuppression
Admission through the emergency department is associated with an increased risk of hospital-acquired pneumonia, as airborne pathogens are easily transmitted in crowded health care settings. [8][9][10]
Common causative pathogens [7]
| Overview of the most common pathogens in HAIs [7] | ||
|---|---|---|
| Type of infection | Most common pathogens | Other causative pathogens |
| Surgical site infections |
| |
| Nosocomial pneumonia |
|
|
| Nosocomial urinary tract infections |
| |
| Bloodstream infections |
| |
| Gastrointestinal infections | ||
Up to 20% of hospitalized patients are readmitted within 30 days of discharge. Monitor these patients closely for HAIs with drug-resistant organisms. [12]
Overview
| Overview of hospital-acquired infections [13][14] | |||||
|---|---|---|---|---|---|
| Conditions | Risk factors | Diagnostic criteria [14] | Initial management steps | ||
| Intravascular catheter-related bloodstream infection [15] |
|
|
| ||
| Catheter-associated urinary tract infection (CAUTI) [16] |
|
|
| ||
| Nosocomial pneumonia [17][18] |
|
| |||
|
Surgical site infection (SSI) [14][19][20] |
|
|
| ||
| Clostridioides difficile infection [21][22][23][24] |
|
|
| ||
Management
Consider HAIs in patients who have recently been hospitalized or undergone a medical intervention and present with new-onset infectious symptoms (e.g., fever, cough, dysuria, pus, diarrhea) and/or unexplained clinical deterioration (e.g., hypotension, increased ventilator support, altered mental status). The approach to management may vary depending on the site of infection and is covered in detail in dedicated articles. The general approach to a suspected HAI is briefly described here.
-
Medical history and examination focusing on:
- Thorough chart review of recent (or current) hospitalization
- Assessment of indwelling lines and tubes, implanted devices, and surgical sites for signs of infection or inflammation
-
Diagnostics
- Routine laboratory studies for suspected infection, including:
- CBC, ESR, CRP, procalcitonin
- Blood cultures
- Consider urinalysis.
- Additional directed workup as needed; examples include:
- Cultures and/or PCR from the likely site(s) of infection
- Imaging studies of the likely site(s) of infection
- Routine laboratory studies for suspected infection, including:
-
Management
- Management of sepsis
- Empiric or targeted antibiotic therapy of the underlying infection
- Consult infectious disease specialists for the management of MDRO infections.
- Determine the need for PPE and follow isolation precautions as needed.
In the emergency department, consider early implementation of infection prevention and control measures (e.g., empiric isolation) in patients with suspected airborne infections or risk factors for MDRO colonization. [9][28]
Consider the risk of MDRO colonization when prescribing antibiotics. [8]
Related One-Minute Telegram
- One-Minute Telegram 112-2024-3/3: Pick midlines over PICC for OPAT
- One-Minute Telegram 87-2023-2/3: Breathe easier: a breakthrough in preventing ventilator-associated pneumonia
- One-Minute Telegram 49-2022-3/3: A care bundle to reduce bloodstream infections in hemodialysis
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