A 12 year old child presents with fever and cervical lymphadenopathy. Oral examination shows a grey membrane on the right tonsil extending to the anterior pillar. Which of the following medium will be ideal for the culture of the throat swab for rapid identification of the pathogen?
The symptoms of the given case are suggestive of C. diphtheria infection.

On Loeffler’s serum slope, C. diphtheriae grows after 4–6 hours at 37°C producing small, circular, and white opaque colonies. 
If no colonies are seen, the medium is reincubated further for 24 hours.

Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:218
Nutrient agar
Blood agar
Loeffler’s serum slope
LJ medium