Table 1.
Common causes of pediatric community-acquired pneumonia by age
| Age | Etiologic agent |
|---|---|
| Birth – 3 weeks | Group B streptococcus (Streptococcus agalactiae) |
| Gram-negative rods (eg, Escherichia coli) | |
| 3 wk – 3 mo | Viruses (eg, respiratory syncytial virus, parainfluenza viruses, influenza A and B, adenovirus) |
| Chlamydia trachomatis | |
| Streptococcus pneumoniae | |
| 4 mo– 4 y | Streptococcus pneumoniae |
| Viruses (eg, respiratory syncytial virus, parainfluenza viruses, influenza A and B, adenovirus) | |
| Haemophilus influenzae | |
| Group A streptococcus (Streptococcus pyogenes) | |
| Staphylococcus aureus | |
| Mycoplasma pneumoniae | |
| Other streptococcal species (eg, Streptococcus milleri group) | |
| ≥5 y | Mycoplasma pneumoniae |
| Chlamydophila pneumoniae | |
| Streptococcus pneumoniae |