Pathogens in Pneumonia



Here is a quick review of the pathogens causing pneumonia (useful for enumerating differentials in your grand rounds/cases)



TYPICAL ORGANISMS (RISK FACTOR): 



- S. pneumoniae (EtOH use. Concomitant flu, IVDU, endobronchial obstruction) 

- H. influenzae (COPD. smoking, concomitant flu. endobronchial obstruction) 

- Moraxella catarrhalis (COPD, smoking) 

- S. aureus (Concomitant Flu, endobronchial obstruction) 

- Grp A strep 

- Gram-negatives (aspiration; Klebsiela & Acinetobacter — EtOH use; Pseudomonas — COPD. smoking. structural lung disease; Burkholderia — structural lung dsease) 



- Anaerobes (EtOH use, aspration, endobronchial obstruction) 



ATYPICAL ORGANISMS (RISK FACTOR): 



- Legionella spp (COPD, smoking. hotel or cruise ships) 

- Mycoplasma pneumoniae 

- Chlamydia pneumoniae (COPD, smoking) 



RESPIRATORY VIRUSES: 



- Influenza 

- Rhinovirus 

- Parainfluenza 

- Adenovirus 

- RSV 

- Human metapneumovirus 

- Coronavirus 

- Human bocavirus 

Others: NTMs. MAC (structural lung disease, smoking) 



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