This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
An elderly male patient presented with fever, chest pain and dry cough. On sputum culture growth on charcol yeast extract medium was identified. The organism is likely to be which of the following? 
Select and explain. 
A. H. influenza, B. Moraxella caarrhahs, C. Legionella, D. Burkholderia cepacia
C: Legionella
Answer: C: Legionella 
Explanation: An elderly patient with fever, chest pain and non-productive (dry cough) are characteristic features of legionnaires disease (pneumonia), caused by Legionella pneumophila. Legionella pneumophila grows on buffered charcoal yeast agar. Hemophilus influenzae grows on blood agar, Moraxella catarrhalis grows on nutrient agar and Burkholderia cepacia needs selective media for its growth. Ref: Textbook of Microbiology, Ananthanarayan and Paniker, 7th Edition, Chapter 45, Page 409.