<prompt> The most common causative organism for lobar pneumonia is:Staphylococcus aureusStreptococcus pyogenesStreptococcus pneumoniaeHaemophilus influenzae  <response>: Ans. C. Streptococcus pneumoniaeThe most common organisms which cause lobar pneumonia are Streptococcus pneumoniae, also called pneumococcus. MC typical pneumonia: strept. pneumonia MC of atypical pneumonia: Mycoplasma MC nosocomial pneumonia: gram negative bacilli MC early VAP: Streptococcus MC late VAP: pseudomonas MC VAP: pseudomonas MC pneumonia in cystic fibrosis: pseudomonas MC pneumonia resulting in ICU admission: streptococcus MCC pneumonia in HIV: tuberculosis MC pneumonia in smokers: Strept. pneumonia MC trigger for asthma exacerbation: Rhinovirus. MC cause exacerbation of COPD: H. influenza 