Pneumonia is one of the most common conditions encountered by primary care providers. Certain organisms cause pneumonia in particular age groups. For example, group B streptococci, Gram-negative bacilli Escherichia coli in particular) and, rarely, Listeria monocytogenes cause pneumonia in neonates. In infants younger than 3 months, group B streptococci and organisms encountered by older children occasionally cause pneumonia, as does Chlamydia trachomatis. Older infants and preschoolers are at risk for infection with Streptococcus pneumoniae and Haemophilus influenzae. In children older than 5 years, S pneumoniae and Mycoplasma pneumoniae are the key pathogens. Let the patient's age, history, clinical presentation, and radiographic findings guide your choice of therapy. Even though most patients with uncomplicated pneumonia can be treated as outpatients, close follow-up is important. Hospitalize patients younger than 6 months and those with complications.
