Johns Hopkins ABX Guide
Pneumonia, Community-Acquired (Adult)
PATHOGENS
Commonly encountered organisms are listed below:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Chlamydophila pneumoniae
- Legionella species
- Mycoplasma pneumoniae
- Viruses:
- Mycobacterium tuberculosis
- Nocardia
- Group A Streptococcus
- Neisseria meningiditis
- Anaerobes
- Gram negatives
- In some CAP series, it may account for 5-10% of cases.
- Risks include COPD, current corticosteroid use, and prior antibiotic therapy.
- Severe CAP: GN bacterial pneumonia is more common in severe cases and is associated with higher mortality.
- Risks include COPD, current corticosteroid use, and prior antibiotic therapy.
- In some CAP series, it may account for 5-10% of cases.
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Last updated: January 17, 2026
Citation
Auwaerter, Paul G. "Pneumonia, Community-Acquired (Adult)." Johns Hopkins ABX Guide, The Johns Hopkins University, 2026. Johns Hopkins Guides, www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540442/3.7/Pneumonia_Community_Acquired__Adult_.
Auwaerter PG. Pneumonia, Community-Acquired (Adult). Johns Hopkins ABX Guide. The Johns Hopkins University; 2026. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540442/3.7/Pneumonia_Community_Acquired__Adult_. Accessed January 20, 2026.
Auwaerter, P. G. (2026). Pneumonia, Community-Acquired (Adult). In Johns Hopkins ABX Guide. The Johns Hopkins University. https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540442/3.7/Pneumonia_Community_Acquired__Adult_
Auwaerter PG. Pneumonia, Community-Acquired (Adult) [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2026. [cited 2026 January 20]. Available from: https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540442/3.7/Pneumonia_Community_Acquired__Adult_.
* Article titles in AMA citation format should be in sentence-case
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