You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Community acquired pneumonia is most commonly caused by: September 2005 and March 2008 and explain in detail?
Ans. B: Streptococcus pneumoniae The term community-acquired pneumonia is usually reserved for people who have pneumonia caused by one of the more common bacteria or viruses. Streptococcus pneumonia is the most common cause of community-acquired acute pneumonia. Gram-negative rods (Enterobacteriaceae and Pseudomonas species) and S.aureus are the most common isolates in hospitalacquuired pneumonia; unlike community-acquired pneumonias, S.pneumoniae is not a major pathogen in hospitalacquuired pneumonia. Haemophilus influenzae, Chlamydia pneumoniae, and Mycobacterium pneumoniae are the other common bacterial causes. Common viral causes include respiratory syncytial virus (RSV), adenoviruses, influenza A and B viruses, metapneumovirus, and parainfluenza viruses.