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
A patient presents with lower gastrointestinal bleed. Sigmoidoscopy shows ulcer in the sigmoid. Biopsy from this area shows flask-shaped ulcers. Which of the following is the most appropriate treatment ? 
Select and explain. 
A. Intravenous ceftriaxone, B. Intravenous metronidazole, C. Intravenous steroids and sulphasalazine, D. Hydrocoisone enemas
B: Intravenous metronidazole
Answer: B: Intravenous metronidazole 
Explanation: Ans. is 'b' i.e., Intravenous metronidazole Flask-shaped ulcer in a patient of GI bleed suggests amebiasis (amoebic dysentry). Drug therapy for amoebiasis Asymptomatic carrier --> Luminal agents (Iodoquinol, Paromomycine) Diloxanide furoate is the DOC. Acute colitis --> Metronidazole or Tinidazole + Luminal agent. Liver abscess Metronidazol or Tinidazole or ornidazole + Luminal agent.