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': 'Exfoliative toxin A which causes generalized desquamation is secreted by the following: \nSelect and explain. \nA. Staphylococci, B. Streptococci, C. Pneumococcus, D. Pseudomonas', 'role': 'user'}, {'content': "Answer: A \nExplanation: Exfoliative toxins are epidermolytic toxins of S aureus are two distinct proteins of the same molecular weight. Exfoliative toxin A is encoded by eta located on a phage and is heat stable (resists boiling for 20 minutes). Exfoliative toxin B is plasmid mediated and heat labile. These epidermolytic toxins yield the generalized desquamation of the staphylococcal scalded skin syndrome by dissolving the mucopolysaccharide matrix of the epidermis. The toxins are superantigens. Ref: Brooks G.F., Carroll K.C., Butel J.S., Morse S.A., Mietzner T.A. (2013). Chapter 13. The Staphylococci. In G.F. Brooks, K.C. Carroll, J.S. Butel, S.A. Morse, T.A. Mietzner (Eds), Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e.", 'role': 'assistant'}]