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
In pontaic fever, which antigen is seen in urine? 
Select and explain. 
A. Lipopolysaccharide-1, B. Lipopolysaccharide-2, C. Lipopolysaccharide-4, D. Lipopolysaccharide-6
A: Lipopolysaccharide-1
Answer: A: Lipopolysaccharide-1 
Explanation: Ans. is 'a' i.e., Lipopolysaccharide-1 Legionella are classified into serogroup on the basis ofgroup specific lipopolysaccharide (somatic antigen or 'O' antigen). Legionella pneumophila sero-group-1 (LP-1) is the most common infecting organism. Urine test detect LP-1.