This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Causative organism of late prosthetic valve endocarditis is : \nSelect and explain. \nA. Streptococcus viridans, B. Proteus mirabilis, C. Beta haemolytic streptococci, D. Staphylococci', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Streptococcus Viridans Prosthetic valve endocarditis is of two typesEarly onset endocarditis - onset of symptoms within 60 days of surgery.Late onset endocarditis - onset of symptoms after 60 days of surgeryMC Organism causing - Early onset endocarditis - Staph epidermidis* Late onset endocarditis - Streptococci (Includes viridans streptococci, streptococcus bovis, other non-group A streptococci)But this classification into late and early onset endocarditis is outdated (Note, that the question belongs to the time when this classification was in use)Harrison 15/e divides Prosthetic valve endocarditis into :less than 2 month2-12 monthsMore 12 months after surgeryMC organisms causing prosthetic valve endocarditis according to Harrison 15/e -less than 2 month - Coagulase-negative staphylococci (Staph, epidermidis is a coagulas negative staphylococci)2-12 month - Same as in less than 2 monthmore than 12 months - Streptococci (includes viridans streptococci, streptococcus bovis, other non-group A streptococci)", 'role': 'assistant'}]