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
Phenylalanine deaminase test is positive in ? 
Select and explain. 
A. Salmonella, B. Proteus, C. Vibrio cholerae, D. Helicobacter
B: Proteus
Answer: B: Proteus 
Explanation: Ans. is 'b' i.e., Proteus The distinctive character of proteus genus is deamination of phenyl alanine to phenyl pyruvic acid (PPA + ye)