Nosocomial Infections
Basics
Description
- Health care–associated infections (HAIs)
- Infection must not have been present or incubating on admission to a health care facility.
- CDC categories:
- Catheter-associated urinary tract infection (CAUTI)
- Surgical site infection (SSI)
- Ventilator-associated pneumonia (VAP)
- Central line–associated bloodstream infection (CLABSI)
- Clostridium difficile infection (CDI; C. diff, C. difficile, CDAD)
- The National Healthcare Safety Network (NHSN) at www.cdc.gov/nhsn monitors emerging HAI pathogens and their mechanisms of resistance to promote current prevention strategies.
- Medicare and Medicaid will not pay for the treatment of certain HAI including CAUTIs, CLABSIs, and SSIs.
Epidemiology
- CAUTI
- 0.2 to 4.8 per 1,000 catheter days
- Hospital stay increased by 1 to 3 days
- Cost up to $600 per infection
- VAP
- 10% of ventilated patients develop VAP.
- Hospital stay increased by 11 to 13 days
- Cost up to $40,000 per infection
- CLABSI
- 41,000 infections annually
- Hospital stay increased by 7 to 20 days
- Cost up to $56,000 per infection
- SSI
- Hospital stay increased by 7.3 days
- Cost >$3,000 per infection
- May not be apparent until 1 month after surgery
- CDI (see topic “Clostridium Difficile Infection”)
Incidence
- 1 of 25 inpatients in the United States has at least one HAI (1).
- 722,000 HAIs in U.S. acute care hospitals (2)
- UTI: 13% of HAIs (2)
- Pneumonia: 22% of HAIs (2)
- Bloodstream infection: 10% of HAIs (2)
- SSI: 22% of HAIs (3)
- C. difficile infection: 12% of HAIs (2). Infections caused by gram-negative rods resistant to almost all antibiotics are increasing. Up to 70% of nosocomial infections are resistant to at least one previously active antimicrobial.
Etiology and Pathophysiology
- Endogenous spread: Patient host flora causes invasive disease (most common).
- Exogenous spread: flora acquired from within health care facility
- Causative organisms
- UTI: Escherichia coli, Klebsiella spp., Serratia spp., Enterobacter, Pseudomonas aeruginosa, Enterococcus spp., Candida albicans (2)
- Pneumonia: aerobic gram-negative bacilli, Staphylococcus aureus, P. aeruginosa, Streptococcus spp. (2)
- Bloodstream infection: Staphylococcus spp., Candida spp., Enterococcus spp., gram-negative bacilli (2)
- SSI: S. aureus, gram-negative bacilli, Enterococcus spp., Streptococcus spp., Enterobacter spp., Bacteroides spp. (2)
Risk Factors
- Extremes of age
- Invasive surgical procedures (abdominal surgeries, orthopedic surgeries, urogynecologic surgeries, neurosurgery)
- Use of indwelling medical devices
- Chronic disease (including diabetes, renal failure, and malignancy)
- Immunodeficiency
- Malnutrition
- Medications (recent antibiotics, proton pump inhibitors, and sedatives)
- Colonization with pathogenic strains of flora
- Breakdown of mucosal/cutaneous barriers, including trauma and battle wounds
- Anesthesia
- Lack of attention to detail with universal precautions
General Prevention
- Prevention should target both patient-specific and facility-related risk factors.
- On entering and leaving any patient room (4)
- After contact with blood, excretions, body fluids, wound dressings, nonintact skin, mucous membranes (4)
- Before using and after removing gloves (gloves are permeable to bacteria)
- When moving hands from contaminated to clean body site (4)
- Alcohol-based products are satisfactory when hands are not visibly soiled (4).
- Soap and water should be used when surfaces are visibly soiled or when contact with spores is anticipated.
- Antibiotic stewardship—appropriate selection of antimicrobial therapy includes the following:
- Judicious use of antibiotics to reduce the emergence of multidrug-resistant organisms and the occurrence of CDI
- Use of narrow-spectrum early-generation antibiotics when possible
- Taking an antibiotic “time out” at 72 hours to review the patient’s clinical status and culture results and eliminate (“streamline”) any redundant or unnecessary antibiotics
- Use shorter courses of antibiotics when appropriate.
- Hospital-based surveillance programs and antibiograms
- Infection control programs with specially trained employees (4)
- Employee education on prevention of HAIs (4)
- Disinfect hospital rooms with hydrogen peroxide vapor or UV irradiation in addition to standard cleaning reduces environmental contamination and the risk of infection with multidrug-resistant organisms.
- Minimize invasive procedures.
- Caregiver stethoscope cleaning
- Stethoscope bacterial contamination is common. Regular cleaning with alcohol-based preparations reduces bacterial load. Evidence is lacking to confirm whether stethoscope contamination causes nosocomial infections.
- Contact precautions
- Important for pathogens spread by direct contact including methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococcus (VRE), C. difficile, extended-spectrum β-lactamase–producing gram-negative rods, and carbapenemase-producing gram-negative rods
- Droplet precautions
- Infectious particles measure >5 μm.
- Institute for pathogens shed via talking, coughing, sneezing, mucosal shedding, airway suctioning, and bronchoscopy. These include Neisseria meningitidis, influenza, Haemophilus influenzae, Corynebacterium diphtheriae, and Bordetella pertussis.
- Airborne precautions
- Infectious particles measure <5 μm.
- Institute for pathogens shed via coughing including tuberculosis, varicella-zoster virus, and measles.
- Contact precautions
- Infection-specific measures
- CAUTI
- Employee education, training, and written guidelines on urinary catheters (indications, placement, maintenance) (5)[C]
- Sterile catheter placement technique (5)[C]
- Closed urine collection system (5)[C]
- Nurse-driven protocols for catheter removal
- Document indication, date of insertion, name of person performing insertion, daily catheter checks, and justification for ongoing use (1)[C].
- Do not confuse catheter-associated asymptomatic bacteriuria with CAUTI.
- Do not screen for bacteriuria with routine urine culture at time of catheter removal.
- VAP
- CLABSI
- Use order “bundles” to improve adherence to catheter insertion guidelines.
- Hand hygiene/glove use
- SSI
- CDI
- Gloves combined with hand hygiene with soap and water (Spores are resistant to alcohol-based products.) (1)
- Continue contact precautions for at least 48 hours after diarrhea has resolved (6)[C].
- C. difficile is associated with the use of proton pump inhibitors: H2 blockers are preferred for acid suppression (6).
- CAUTI
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Citation
Domino, Frank J., et al., editors. "Nosocomial Infections." 5-Minute Clinical Consult, 33rd ed., Wolters Kluwer, 2025. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688516/all/Nosocomial_Infections.
Nosocomial Infections. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2025. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688516/all/Nosocomial_Infections. Accessed November 6, 2024.
Nosocomial Infections. (2025). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (33rd ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688516/all/Nosocomial_Infections
Nosocomial Infections [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2025. [cited 2024 November 06]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688516/all/Nosocomial_Infections.
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