This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mycobacterial Diseases (TB, Leprosy and MAC), Subject name: Pharmacology
[{'content': 'Which of the following anti TB drugs acts on extracellular organisms and is bactericidal drug? \nSelect and explain. \nA. Isoniazid, B. Streptomycin, C. Rifampicin, D. Ethambutol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Streptomycin is the only anti-TB drug which acts on extracellular organisms and is bactericidal. All first line antitubercular drugs are bactericidal except ethambutol which is bacteriostatic. Impoant points about first line ATT: Drug Action Hepatotoxic Bacteria Inhibited Isoniazid CIDAL Yes Both Rifampicin CIDAL Yes Both Pyrazinamide CIDAL Yes Intracellular Ethambutol STATIC No Both Streptomycin CIDAL No Extracellular', 'role': 'assistant'}]