Table 1.

List of pneumonia pathogens according to patient population

Patient Population	Pathogens
Otherwise healthy adult, bacterial	Streptococcus pneumoniae Mycoplasma pneumoniae Staphylococcus aureus Legionella pneumophila Haemophilus influenzae Chlamydophila pneumoniae Moraxella catarrhalis
Otherwise healthy adult, viral	Human rhinovirus Influenza Human metapneumovirus Parainfluenza virus Respiratory syncytial virus Coronavirus Adenovirus
Adults with health care exposure	Pseudomonas aeruginosa S aureus Klebsiella pneumoniae Escherichia coli
Pediatric patients – by age Birth to 20 d 20 d to 4 mo 4 mo to 5 y School-aged children	E coli Listeria monocytogenes Group B streptococci Chlamydia trachomatis Streptococcus pneumoniae C trachomatis Streptococcus pneumoniae M pneumoniae Respiratory syncytial virus Influenza Parainfluenza Adenovirus Rhinovirus C pneumoniae M pneumoniae Streptococcus pneumoniae M catarrhalis H influenzae S aureus
Unusual and opportunistic infectious etiologies	Pneumocystic jiroveci Histoplasma capsulatum Blastomyces Coccidioidomycosis Aspergillus Candida albicans Mucorales Cryptococcus neoformans Coxiella burnetii Mycobacterium tuberculosis