The most common causative organism causing lobar pneumonia is: (A) Staphylococcus aureus, (B) Streptococcus pyogenes, (C) Streptococcus pneumonia, (D) Hemophilus influenza
Answer is C. Although Streptococcus pneumoniae is most common, other organisms must also be considered in light of the patient&;s risk factors and severity of illness.(Ref: Harrison's 18/e p2131)