The most frequent bacterial cause of community acquired pneumonia (CAP) is Streptococcus pneumoniae.
This bacterium, also known as pneumococcus, is responsible for a significant proportion of CAP cases diagnosed worldwide.
While other organisms like Mycoplasma pneumoniae and Staphylococcus aureus can cause pneumonia, they are less common as primary agents of CAP compared to Streptococcus pneumoniae. Legionella haemophilia is not a typical or common cause.