A child has a respiratory infection with a membrane over Peritonsillar area. A swab was taken from the local area. The appropriate media for culture is
**Core Concept**
The question requires the identification of the appropriate culture medium for a specific type of bacterial infection, which is a common scenario in pediatric medicine. The presence of a membrane over the peritonsillar area suggests a specific type of bacterial infection that requires a particular type of culture medium for optimal growth.
**Why the Correct Answer is Right**
The correct answer is based on the identification of the causative organism, which is likely **Streptococcus pyogenes**, the bacterium responsible for Group A streptococcal infections. This bacterium is commonly associated with peritonsillar abscesses and requires a specific type of culture medium for optimal growth. The correct medium is **Blood agar**, which provides the necessary nutrients for the growth of S. pyogenes, including the hemolysin that breaks down red blood cells.
**Why Each Wrong Option is Incorrect**
**Option A:** **MacConkey agar** is incorrect because it is primarily used for the isolation of gram-negative bacteria, such as E. coli, and is not suitable for the growth of S. pyogenes.
**Option B:** **Chocolate agar** is incorrect because it is typically used for the isolation of Haemophilus and Neisseria species, and is not the optimal medium for S. pyogenes.
**Option C:** **Sabouraud agar** is incorrect because it is used for the isolation of fungi, such as Candida and Aspergillus, and is not suitable for the growth of S. pyogenes.
**Clinical Pearl / High-Yield Fact**
When suspecting a Group A streptococcal infection, it's essential to obtain a throat swab or peritonsillar abscess aspirate for culture, as this will aid in the diagnosis and guide antibiotic therapy.
**Correct Answer:** . Blood agar.