Question

A 6 year old boy has fever and chills, cough, rapid breathing, difficulty breathing and chest pain. Culture from a sample shows a Gram-positive organism. Identify the image.

• A. Streptococcus pneumoniae
• B. Staphylococcus
• C. Propionibacterium
• D. Mycobacterium

Hint:

Alpha-hemolytic, lancet-shaped Gram-positive diplococci causing childhood community-acquired pneumonia.

Answer 1

The Correct Option is A

Step 1: A young child with acute fever, tachypnoea, chest pain and a Gram-positive culture is the textbook presentation of community-acquired pneumococcal pneumonia.
Step 2: The slide shows paired, flame or lancet shaped Gram-positive cocci, characteristic of $Streptococcus\ pneumoniae$. On blood agar it is alpha-hemolytic, giving green partial haemolysis from $H_2O_2$ release.
Step 3: That same hydrogen peroxide injures host DNA and alveolar cells, driving the lung infection, and if it reaches the meninges it causes pneumococcal meningitis.
Step 4: Staphylococci form grape-like clusters, Propionibacterium is an anaerobic skin flora, and Mycobacterium stains acid-fast, so all are excluded.
\[\boxed{\text{Streptococcus pneumoniae}}\]