- Pneumonia is an acute infection of the pulmonary parenchyma caused by viral, bacterial, and fungal pathogens, which causes mild to severe illness and can affect people at any age.1-3
- Community-acquired pneumonia (CAP) refers to pneumonia cases that are acquired in the community as opposed to the hospital setting.2
Types and Causes of Pneumonia
Pneumonia, an infection of the lungs, causes mild to severe illness and can affect people at any age.1 Viral, bacterial, and fungal pathogens can all cause infectious pneumonia.2,3
CAP refers to cases of pneumonia that develop outside of the healthcare setting (i.e., not during or shortly after a stay in hospital, nursing home or other healthcare center).2
CAP is distinguished from hospital-associated pneumonia (HAP) and ventilator-associated pneumonia (VAP), which are caused by a broader range of pathogens that are frequently resistant to currently recommended CAP treatment regimens.2,6-8
Pneumonia Can Occur in a Variety of Patient Types and Different Clinical Settings
- Pneumonias developed outside of a hospital setting6,8
- S. pneumoniae is the most common causative pathogen6
- Mycoplasma pneumoniae, Legionella pneumoniae, and Chlamydophila pneumoniae are also observed6,8
- Pneumonias developed in a hospital after 48 hours but not as a result of mechanical ventilation7
- Often caused by multi-drug resistant organisms including methicillin-resistant Staphylococcus aureus (MRSA), or pseudomonas7
- Pneumonias that occur during or following treatment with mechanical ventilation7
- Often caused by multi-drug resistant organisms (MRSA, pseudomonas)7
Community-acquired bacterial pneumonia (CABP), a subset of CAP, has been defined by the United States Food and Drug Administration (FDA) to refer specifically to acute bacterial infections of the lung parenchyma associated with specific signs and symptoms suggestive of bacterial infection.9
- Centers for Disease Control and Prevention. Pneumonia. March 9, 2020. Available from: https://www.cdc.gov/pneumonia/index.html (accessed October 09 2020).
- Centers for Disease Control and Prevention. Causes of pneumonia. March 9, 2020. Available from: https://www.cdc.gov/pneumonia/causes.html (accessed October 09 2020).
- Centers for Disease Control and Prevention. Fungal Pneumonia. Available from: https://www.cdc.gov/fungal/pdf/cocci-fact-sheet-sw-us-508c.pdf (accessed October 09 2020).
- Musher DM, Abers MS, Bartlett JG. Evolving understanding of the causes of pneumonia in adults, with special attention to the role of Pneumococcus. Clin Infect Dis. 2017;65(10):1736-1744.
- Di Pasquale MF, Sotgiu G, Gramegna A, et al. Prevalence and Etiology of Community-acquired Pneumonia in Immunocompromised Patients. Clin Infect Dis. 2019;68(9):1482-1493.
- Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019;200(7):e45-e67.
- Kalil AC, Metersky ML, Klompas M, et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis. 2016;63(5):e61-e111.
- Acute Community-Acquired Pneumonia (CAP and VAP/HAP). Available at https://www.infectiousdiseaseadvisor.com/home/decision-support-in- medicine/infectious-diseases/acute-community-acquired-pneumonia-cap-and-vap-hap/ (accessed October 09 2020).
- Food and Drug Administration. Community-acquired bacterial pneumonia: Developing drugs for treatment. June 24, 2020. Available from: https:// www.fda.gov/regulatory-information/search-fda-guidance-documents/community-acquired-bacterial-pneumonia-developing-drugs-treatment (accessed October 09 2020).