This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Cocci, Gram Negative Cocci), Subject name: Microbiology
[{'content': 'Which of the following is catalase positive? \nSelect and explain. \nA. Staph epidermidis, B. Enterococcus, C. Streptococcus, D. Pneumococcus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Catalase test is used mainly to differentiate between Staphylococcus(Catalase positive) and Streptococcus (Catalase negative). +ve Catalase test = Bubble formation due to release of nascent O2 from H2O2 by Catalse enzyme in the colony Catalase positive organisms Staphylococcus Pseudomonas aeruginosa Aspergillus fumigatus Candida Enterobacteriaceae except Shigella dysentry type 1', 'role': 'assistant'}]