Pneumonia, Bacterial

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Basics

Bacterial pneumonia is an infection of the pulmonary parenchyma by a bacterial organism.

Description

Bacterial pneumonia can be classified as the following:

  • Community-acquired pneumonia (CAP): acute infection of the pulmonary parenchyma acquired outside of a health care setting or long-term care facility
  • Nosocomial pneumonia: acute infection of the pulmonary parenchyma acquired in health care settings
    • Hospital-acquired pneumonia (HAP): occurs ≥48 hours after admission and did not appear to be incubating at time of admission
    • Ventilator-associated pneumonia (VAP): pneumonia develops >48 hours after endotracheal intubation
    • Health care–associated pneumonia (HCAP): This categorization is no longer used.

Epidemiology

  • In the United States as of 2018, CAP is the eighth most common cause of death (even higher in those >65) and most common cause of death related to infection.
  • Pneumonia causes 3.2 million estimated deaths.
  • HAP is the leading cause of death among nosocomial infections and is one of the leading causes of death in the ICU.
  • Rates of infection are 3 times higher in African Americans than in whites and are 5 to 10 times higher in Native American adults and 10 times higher in Native American children.
  • Mortality rate in children is approximately 1.6 million a year. Hospitalization rate for children with CAP is still highest among the very young ages (<18 months). Respiratory viruses are the most commonly detected causes of pneumonia in children (1).

Incidence
  • CAP: 5 to 6 cases per 1,000 persons with increased incidence occurring in the winter months
  • HAP: 5 to 20 cases per 1,000 admissions; incidence increases 6- to 20-fold in ventilated patients

Etiology and Pathophysiology

  • Pathogenicity of the implicated organisms informs the presentation and antibiotic choice.
  • Adults, CAP
    • Typical (85%): Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, group A Streptococcus, Moraxella catarrhalis
    • Atypical (15%): 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)
  • Pediatric
    • Birth to 3 weeks: E. coli, group B streptococci, Listeria monocytogenes
    • <3 months: Chlamydia trachomatis, S. pneumoniae, H. influenzae
    • 3 months to 18 years
      • Typical: S. pneumoniae
      • Atypical: C. pneumoniae, M. pneumoniae

Risk Factors

  • Immunosuppression:
    • Chronic steroid use (>20 mg/day or >2 mg/kg/day of prednisone for >14 days)
    • HIV/immunoglobulin deficiencies/solid organ transplant/TNF-α inhibitor therapy
  • Chronic health conditions:
    • Asthma, COPD
    • Type 2 DM, chronic renal failure, CHF, liver disease, tobacco use
  • Other:
    • Age >65 years
    • Antibiotic therapy in the past 6 months/resistance to antibiotics
    • Hospitalization for ≥2 days during past 90 days
    • Poor functional status as defined by activities of daily living score

General Prevention

Vaccination recommendations:

  • All children 2 to 59 months of age should be routinely vaccinated with pneumococcal conjugate (PCV13); given at 2, 4, and 6 months of age; a fourth dose at 12 to 15 months of age
  • Adults ≥65 years who are vaccine naïve: should receive PPSV23 only. Adults >65 years old in the high risk group should receive PCV13 followed by pneumococcal polysaccharide (PPSV23) ≥1 year interval.
  • For adults ≥65 years old in the high risk group who have already received PPSV23, a dose of PCV13 is indicated after ≥1 year.
  • Adults 19 to 64 years with tobacco use, chronic heart or lung disease, alcoholism, or chronic liver disease should receive a dose of PPSV23, followed by PCV13 at age 65 and a subsequent PPSV23 ≥1 year after PCV13 and at least 5 years after the previous PPSV23 dose.
  • High-risk adults ≥19 years old with immunocompromising conditions: asplenia, CSF leaks, cochlear implants, HIV infection, immunodeficiencies: 1 dose of PCV13 followed by PPSV23 after ≥8 weeks. A second dose of PPSV23 is recommended for all except those with CSF leak or cochlear implant, it should be given 5 years after first dose. A final dose of PPSV23 should be administered at age 65 and at least 5 years after the previous dose. Those who were previously given PPSV23 should receive a PCV13 dose ≥1 year after last PPSV23. If additional PPSV23 is required, it should be given ≥8 weeks after PCV13 and 5 years after most recent dose of PPSV23.
  • Annual influenza vaccine

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Basics

Bacterial pneumonia is an infection of the pulmonary parenchyma by a bacterial organism.

Description

Bacterial pneumonia can be classified as the following:

  • Community-acquired pneumonia (CAP): acute infection of the pulmonary parenchyma acquired outside of a health care setting or long-term care facility
  • Nosocomial pneumonia: acute infection of the pulmonary parenchyma acquired in health care settings
    • Hospital-acquired pneumonia (HAP): occurs ≥48 hours after admission and did not appear to be incubating at time of admission
    • Ventilator-associated pneumonia (VAP): pneumonia develops >48 hours after endotracheal intubation
    • Health care–associated pneumonia (HCAP): This categorization is no longer used.

Epidemiology

  • In the United States as of 2018, CAP is the eighth most common cause of death (even higher in those >65) and most common cause of death related to infection.
  • Pneumonia causes 3.2 million estimated deaths.
  • HAP is the leading cause of death among nosocomial infections and is one of the leading causes of death in the ICU.
  • Rates of infection are 3 times higher in African Americans than in whites and are 5 to 10 times higher in Native American adults and 10 times higher in Native American children.
  • Mortality rate in children is approximately 1.6 million a year. Hospitalization rate for children with CAP is still highest among the very young ages (<18 months). Respiratory viruses are the most commonly detected causes of pneumonia in children (1).

Incidence
  • CAP: 5 to 6 cases per 1,000 persons with increased incidence occurring in the winter months
  • HAP: 5 to 20 cases per 1,000 admissions; incidence increases 6- to 20-fold in ventilated patients

Etiology and Pathophysiology

  • Pathogenicity of the implicated organisms informs the presentation and antibiotic choice.
  • Adults, CAP
    • Typical (85%): Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, group A Streptococcus, Moraxella catarrhalis
    • Atypical (15%): 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)
  • Pediatric
    • Birth to 3 weeks: E. coli, group B streptococci, Listeria monocytogenes
    • <3 months: Chlamydia trachomatis, S. pneumoniae, H. influenzae
    • 3 months to 18 years
      • Typical: S. pneumoniae
      • Atypical: C. pneumoniae, M. pneumoniae

Risk Factors

  • Immunosuppression:
    • Chronic steroid use (>20 mg/day or >2 mg/kg/day of prednisone for >14 days)
    • HIV/immunoglobulin deficiencies/solid organ transplant/TNF-α inhibitor therapy
  • Chronic health conditions:
    • Asthma, COPD
    • Type 2 DM, chronic renal failure, CHF, liver disease, tobacco use
  • Other:
    • Age >65 years
    • Antibiotic therapy in the past 6 months/resistance to antibiotics
    • Hospitalization for ≥2 days during past 90 days
    • Poor functional status as defined by activities of daily living score

General Prevention

Vaccination recommendations:

  • All children 2 to 59 months of age should be routinely vaccinated with pneumococcal conjugate (PCV13); given at 2, 4, and 6 months of age; a fourth dose at 12 to 15 months of age
  • Adults ≥65 years who are vaccine naïve: should receive PPSV23 only. Adults >65 years old in the high risk group should receive PCV13 followed by pneumococcal polysaccharide (PPSV23) ≥1 year interval.
  • For adults ≥65 years old in the high risk group who have already received PPSV23, a dose of PCV13 is indicated after ≥1 year.
  • Adults 19 to 64 years with tobacco use, chronic heart or lung disease, alcoholism, or chronic liver disease should receive a dose of PPSV23, followed by PCV13 at age 65 and a subsequent PPSV23 ≥1 year after PCV13 and at least 5 years after the previous PPSV23 dose.
  • High-risk adults ≥19 years old with immunocompromising conditions: asplenia, CSF leaks, cochlear implants, HIV infection, immunodeficiencies: 1 dose of PCV13 followed by PPSV23 after ≥8 weeks. A second dose of PPSV23 is recommended for all except those with CSF leak or cochlear implant, it should be given 5 years after first dose. A final dose of PPSV23 should be administered at age 65 and at least 5 years after the previous dose. Those who were previously given PPSV23 should receive a PCV13 dose ≥1 year after last PPSV23. If additional PPSV23 is required, it should be given ≥8 weeks after PCV13 and 5 years after most recent dose of PPSV23.
  • Annual influenza vaccine

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