This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
Catalase negative beta-hemolytic Streptococci is 
Select and explain. 
A. Streptococcus Pneumoniae, B. Streptococcus Pyogenes, C. Streptococcus Agalactiae, D. Enterococcus
B: Streptococcus Pyogenes
Answer: B: Streptococcus Pyogenes 
Explanation: Streptococcus pyogenes is catalase negative and beta-hemolytic. On blood agar, after incubation for 24 hours the colonies are small, circular, semi-transparent, low convex discs with an area of clear hemolysis around them ( beta hemolysis). Catalase test: place a loopful of hydrogen peroxide on colonies on the nutrient agar. Prompt effervescence indicates catalase production. No effervescence indicates catalase negative organisms. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 211