This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Catalase negative member of the family Enterobacteriaceae is (NOT RELATED) 
Select and explain. 
A. Salmonella typhi, B. Proteus vulgaris, C. Shigella dysenteriae serotype 1, D. Escherichia coli
C: Shigella dysenteriae serotype 1
Answer: C: Shigella dysenteriae serotype 1 
Explanation: The general finding that members of the family enterobacteriaceae produce catalase has impoant exceptions in Shigella dysenteriae serotype 1 and a few strains of Shigella flexneri (mostly in serotype 4a) which are catalase negative.