You are examining the specimen taken from a child with Otitis. On microscopy you see capsulated lanceolate diplococci and the culture of the specimen shows a draughtsman appearance. What is the diagnosis?
## **Core Concept**
The question describes a microbiological diagnosis based on the microscopic and cultural characteristics of a pathogen isolated from a child with otitis. The key features provided are the presence of capsulated lanceolate diplococci on microscopy and a "draughtsman appearance" on culture. These characteristics are critical for identifying the causative organism.
## **Why the Correct Answer is Right**
The description of "capsulated lanceolate diplococci" is classic for *Streptococcus pneumoniae*. This bacterium is known for its lanceolate (elongated and tapering) shape and for occurring in pairs (diplococci), and many strains are encapsulated. The "draughtsman appearance" or more commonly referred to as a "carrom coin" or "stacked coin" appearance on blood agar is characteristic of *S. pneumoniae* colonies. This appearance is due to the way the colonies grow and the central depression in some colonies. *S. pneumoniae* is a common cause of otitis media among other infections.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Without the specific text of the option, we can't directly address why it's incorrect, but any option not matching *S. pneumoniae* based on the given description would be incorrect.
- **Option B:** Similarly, without specifics, any alternative not aligning with the microbiological features provided would not be the correct diagnosis.
- **Option C:** This would also not be correct for the same reason; it doesn't match the description of *S. pneumoniae*.
- **Option D:** Assuming this is not the correct answer, it would not align with the microbiological characteristics described.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that *Streptococcus pneumoniae* is a leading cause of otitis media in children, and its identification can be made based on characteristic colony morphology on agar plates and microscopic appearance. The presence of a capsule is also a virulence factor that can be detected by specific staining techniques.
## **Correct Answer:** D. Streptococcus pneumoniae.