Streptococcus pneumoniae causes up to 70% of communityacquired
pneumonia cases and atypical pathogens are
responsible for 30–40% of cases. The other bacteria which
cause community-acquired pneumonia besides Streptococcus
pneumoniae are Haemophilus infuenzae, Staphylococcus aureus and
Gram-negative bacilli. Legionella, Mycoplasma pneumoniae and
Chlamydia pneumoniae are the atypical agents which cause CAP