Classic organisms associated with atypical pneumonia:
(1) Chlamydophila pneumoniae (formerly called Chlamydia pneumoniae)
(2) Mycoplasma pneumoniae
(3) Legionella species
Other organisms that may present as an atypical pneumonia:
(1) deep fungus including Cryptococcus neoformans
(2) Chlamydophila psittaci (formerly called Chlamydia psittaci)
(3) typical or atypical mycobacterium
(4) Coxiella burnetti (Q fever)
(5) Francisella tularensis
(6) respiratory viruses (influenza, parainfluenza, adenovirus, metapneumovirus, etc)
(7) Babesia
(8) Pneumocystis pneumonia
The use of a panel of molecular markers can help sort throught the maze of potential pathogens quickly.