This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
[{'content': 'A 34-year-old pregnant female presented to the ER with fever, backache, headache and myalgias. Blood cultures were collected and subjected to examination. Microbiological examination revealed positive motility at 25 degree Celsius and catalase positivity, Esculin positivity and positive growth in 6.5% NaCl. The colonies are as shown on blood agar plate given below. Gram Staining Which of the following is the most common route of transmission of the above organism: - \nSelect and explain. \nA. Aerosol person to person transmission, B. Feco-oral route, C. Ingestion of contaminated food, D. Sexually transmitted', 'role': 'user'}, {'content': 'Answer: C \nExplanation: This is a case of Listeria monocytogenes infection. The blood culture plate shows beta hemolysis. The gram stain shows gram positive coco-bacilli. Most common route of infection is the GI tract. Found in processed foods. It is invasive. Produces Listeriolysin-O which allows bacterium to escape from cell membrane and cause septicemia. May cross BBB to cause meningitis and encephalitis.', 'role': 'assistant'}]