This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
[{'content': 'Multidrug-resistant S. typhi ) are resistant to all except- \nSelect and explain. \nA. Chloramphenicol, B. Ampicillin, C. Ciprofloxacin, D. Septran', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Isolates of S. typhi resistant to chloramphenicol, ampicillin, and co-trimoxazole designated as multidrug-resistant S. typhi . Ciprofloxacin became drug of choice for typhoid fever in patients of all age groups, infected or likely to be infected with fully drug susceptible S. typhi or MDR-ST. Alternative : Third-generation cephalosporins (cefixime for 7 to 14 days or ceftriaxone for 10 to 14 days) and azithromycin (for 7 days).', 'role': 'assistant'}]