Pneumonia: Causes

Key points

• Community acquired pneumonia (CAP) may be caused by the following infectious agents:
• Streptococcus pneumoniae (accounts for around 80% of cases)
• Haemophilus influenzae
• Staphylococcus aureus: commonly after the 'flu
• atypical pneumonias (e.g. Due to Mycoplasma pneumoniae)