What is Catalase negative beta-hemolytic Streptococci is and explain in detail?
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