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: Ophthalmology
[{'content': 'Late onset endophthalmitis after cataract surgery is most often caused by: \nSelect and explain. \nA. Staphylococcus Epidermidis, B. Pseudomonas, C. Streptococcus Pyogenes, D. Propionobacterium Acnes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Propionobacterium Acnes - most frequent isolate in chronic postoperative endophthalmitis followed by S.epidermidis, aerobic streptococci and Actinomyces species. Most frequent repoed organism is Propionobacterium Acnes. Ref: Clinical Eye Atlas - Page 700; Complications in Phacoemulsification: Avoidance, Recognition, and Management - Page 304.', 'role': 'assistant'}]