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 person returns to Delhi from Bangladesh after 2 days and has diarrhoea. Stool examination shows RBCs in Stool. The likely organism causing is ? \nSelect and explain. \nA. Enteropathogenic E. Coli, B. Enterotoxigenic E. Coli, C. Salmonella typhi, D. Shigella dysentriae', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Shigella Dysentriae . The person is suspected to have traveller's diarrhoea. . The most common cause of traveller's diarrhoea is E.coli , but the strains of the E.coli (Enterotoxigenic & Enteropathogenic) given in the choice do not produce invasive illness i.e presence of blood in stool. . It is a feature of Enterohemorrhagic E.coli . Now the choice is between Salmonella & Shigella diarrhoea are . Both these organisms produce invasive disease i.e dysentery or inflammatory diarrhoea . But Shigella & Salmonella can be differentiated on the basis of incubation period. i) Shigella (1-2days) ii) Salmonella --)0. (10-14 days)", 'role': 'assistant'}]