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.
  • Hand hygiene—thoroughly wash hands (1)[B].
    • 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.
  • Isolation of known pathogen carriers (4)[A]
    • 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
      • Glove when entering room (4)[B]
      • Gown if clothing will touch patient or environment (4)[B]
    • 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.
      • Mask when entering room (4)[B].
    • Airborne precautions
      • Infectious particles measure <5 μm.
      • Institute for pathogens shed via coughing including tuberculosis, varicella-zoster virus, and measles.
      • Fit-tested National Institute for Occupational Safety and Health (NIOSH)-approved ≥ N95 respirator on entering room (4)[B]
  • 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]
      • Use catheter only for necessary duration and remove as early as possible (5)[B].
      • 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
      • Intubate only when necessary; use noninvasive positive pressure ventilation if possible (1)[A].
      • Perform oral decontamination with oral chlorhexidine (1)[B].
      • Minimize the need for sedation (1)[B] and provide daily interruption of sedation (1)[A].
      • Provide exercise and ambulation early (1)[B].
      • Elevate head to 30 to 45 degrees (1)[C].
    • CLABSI
      • Educate staff about appropriate use of IV catheters (indications, placement, maintenance) (1)[B].
      • Place catheters using sterile technique (including chlorhexidine prep (1)[A] and maximal barrier precautions) (1)[B].
      • Use order “bundles” to improve adherence to catheter insertion guidelines.
      • Daily chlorhexidine bath; chlorhexidine dressing for patients >2 months old (1)[A]
      • Promptly remove catheter when no longer clinically indicated (1)[B].
      • Hand hygiene/glove use
      • Regularly monitor catheter site (1)[A].
    • SSI
      • Proper surgical hand hygiene (1)[B]
      • Prophylactic antibiotic therapy when indicated (1)[A]; eliminate underlying infections before surgery if possible (1)[A].
      • Remove hair with electric clippers/depilatory agent prior to incision (1)[B].
      • Poor postoperative blood sugar control increases risk of infection (1)[B].
    • 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].
      • Limit use of fluoroquinolones, cephalosporins, and clindamycin if possible (6)[B].
      • C. difficile is associated with the use of proton pump inhibitors: H2 blockers are preferred for acid suppression (6).

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