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
[{'content': 'A farmer presents with pustules, which show Gram Positive Cocci on smear. Culture shows Beta hemolysis, and organisms are Catalase negative. To show that the identified organism is group A streptococci, which of the following test should be done? \nSelect and explain. \nA. Bacitracin sensitivity, B. Optochm sensitivity, C. Novobiocin sensitivity, D. Bile solubility', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Streptococci are catalase negative and beta hemolytic. Group A beta hemolytic streptococci can be differentiated from other beta hemolytic streptococci by bacitracin sensitivity. Streptococcus pyogenes is bacitracin sensitive whereas streptococcus agalactiae is bacitracin resistant. Both are beta hemolytic. Ref: Textbook of Microbiology, Ananthanarayan and Paniker, 7th Edition, Chapter 23, Page 203-205.', 'role': 'assistant'}]