Description

Bacterial pneumonia can be classified as:

• Community-acquired pneumonia (CAP): Lower-respiratory tract infection not acquired in a hospital, long-term care facility, or during other recent contact with the health care system.
• Hospital-acquired pneumonia (HAP): Pneumonia that occurs ≥48 hours after admission and did not appear to be incubating at the time of admission.
• Ventilator-associated pneumonia (VAP): Pneumonia that develops >48–72 hours after endotracheal intubation.
• Health care–associated pneumonia (HCAP): Pneumonia that occurs in a nonhospitalized patient with extensive health care contact, such as:
  • IV therapy/Wound care within the past 30 days
  • Residing in a nursing home/long-term care facility
  • Hospitalization in an acute care hospital for ≥2 days within the past 90 days
  • Visited a hospital/hemodialysis clinic within the past 30 days

Epidemiology

• Influenza and pneumonia is the 8th leading cause of death in the US, with about 53,692 deaths in 2010.
• HAP is the leading cause of death among hospital-acquired infections and is the primary cause of death in the ICU.

• CAP: 5–11 cases/1,000 persons with increased incidence occurring in the winter months
• HAP: 5–10 cases/1,000 admissions;incidence increase 6–20 fold in ventilated patients (1).

Risk Factors

• CAP:
  • Age >65 years
  • HIV/Immunocompromised
  • Recent antibiotic therapy/resistance to antibiotics
  • Asthma, CAD, COPD, chronic renal failure, CHF, diabetes, liver disease, neoplasms
• VAP, HAP, HCAP:
  • Hospitalization for ≥2 days during past 90 days
  • Severe illness
  • Antibiotic therapy in the last 6 months
  • Poor functional status as defined by activities-of-daily living score
  • Immunosuppression

General Prevention

• All children 2–59 months of age should be routinely vaccinated with PCV-13; given at 2, 4, and 6 months of age; a 4th at 12–15 months of age. PCV-13 is now currently FDA approved for those >50 years age (2).
• 23-valent pneumococcal polysaccharide vaccine is recommended for (2):
  • Age ≥65. Second dose recommended if patient received vaccine 5 years prior and was <65 years at the time of the 1st vaccination.
  • Age 19–64 with chronic cardiovascular disease, chronic pulmonary disease (including asthma), diabetes mellitus, chronic liver disease, CSF leaks, cochlear implants, alcoholism, or who smoke cigarettes/live in chronic care facilities. Revaccination not recommended <65 years of age.
  • Age 19–64 who are immunocompromised. Second dose recommended if ≥5 years have elapsed since 1st dose.
• Annual influenza vaccine is recommended according to current guidelines.

Etiology

• Adults, CAP:
  • Typical: Streptococcal pneumoniae, Haemophilus influenzae, Staphylococcus aureus, group A Streptococcus, Moraxella catarrhalis
  • Atypical: Legionella sp., Mycoplasma pneumoniae, Chlamydophila pneumoniae
• Adults, HCAP/HAP/VAP:
  • Aerobic gram-negative bacilli: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter sp.
  • Gram-positive cocci: Streptococcus sp. and S. aureus (including MRSA)
• Children (3)[B]:
  • Birth to 20 days: E. coli, group B streptococci, Listeria monocytogenes
  • 3 weeks to 3 months: Chlamydia trachomatis, S. pneumoniae
  • 4 months to 18 years:
    • Typical: S. pneumoniae
    • Atypical: C. pneumoniae, M. pneumoniae