An 8 years old child is having sore throat with grey-white membrane in throat. Throat swab culture is showing following growth. The causative organism is-
An 8 years old child is having sore throat with grey-white membrane in throat. Throat swab culture is showing following growth. The causative organism is-
💡 Explanation
## **Core Concept**
The question describes a clinical scenario suggestive of diphtheria, a bacterial infection characterized by the formation of a grey-white membrane in the throat. Diphtheria is caused by *Corynebacterium diphtheriae*. The diagnosis is often confirmed by throat swab culture.
## **Why the Correct Answer is Right**
The correct answer, *Corynebacterium diphtheriae*, is the causative organism of diphtheria. This bacterium produces a toxin that leads to the formation of a pseudomembrane in the throat, which is a hallmark of the disease. The organism is a Gram-positive rod that can be identified on culture.
## **Why Each Wrong Option is Incorrect**
* **Option A:** *Streptococcus pneumoniae* can cause various infections, including pneumonia and meningitis, but it is not typically associated with the formation of a grey-white membrane in the throat.
* **Option B:** *Streptococcus pyogenes* (Group A beta-hemolytic streptococcus) causes strep throat, which can present with a sore throat but not typically with a grey-white membrane.
* **Option D:** *Haemophilus influenzae* can cause a range of infections, including otitis media, epiglottitis, and pneumonia, but it is not characteristically associated with a grey-white throat membrane.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that diphtheria can be prevented by vaccination (DTP vaccine). The disease can lead to serious complications, including respiratory obstruction and cardiac failure, making prompt diagnosis and treatment crucial.