A child presents with a white patch over the tonsils, diagnosis is best made by culture in: (A) Loeffler medium, (B) LJ medium, (C) Blood agar, (D) Tellurite medium
Answer is D. White patch over the tonsil is suggestive of infection with cCorynebacteriumdiphtheriae. It can be confirmed by culture in Tellurite blood agar. Tellurite inhibits the growth of most other bacteria acting as a selective agent for diphtheria bacilli. Diphtheria bacilli reduce Tellurite to metallic tellurium which incorporates into colonies giving them a grey or black color. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 242