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': "Best selective media for Salmonella ? \nSelect and explain. \nA. Thiosulphate citrate bile salt agar(TCBS), B. Wilson and Blair's brilliant-green bismuth sulphite agar medium, C. Sorbitol MaCconkey agar, D. All of the above", 'role': 'user'}, {'content': "Answer: B \nExplanation: Wilson and Blair's brilliant-green bismuth sulfite agar (WBBS) -Best selective and indicator medium used for the isolation of Salmonella species. Bismuth sulfite, brilliant green - inhibitors- hinder the growth of most bacteria while allowing salmonella to grow. Ferrous sulphate- Reacts with H2S - formation of ferrous sulfide-brown-black coloration and also diffuses into the surrounding medium, giving a brown -black halo. Option 1: Thiosulphate citrate bile salt agar(TCBS) is used for Vbrio. Option 3: Sorbitol MaCconkey agar -For EHEC (Enterohaemorrhagic Escherichia coli).", 'role': 'assistant'}]