Question:easy
What is the most common bacterial cause of lower respiratory tract infection in a 3 year old child?
What is the most common bacterial cause of lower respiratory tract infection in a 3 year old child?
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Among bacteria, pneumococcus leads childhood pneumonia (RSV leads overall).
Updated On: Jun 24, 2026
- Klebsiella
- H. influenzae
- Streptococcus pneumoniae
- Staphylococcus aureus
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: Note the overall leader. If viruses were included, RSV would top the list of childhood pneumonia, but every option here is bacterial, so the stem targets the commonest bacterial agent.
Step 2: Name the top bacterium. Streptococcus pneumoniae (the pneumococcus) is the most frequent bacterial cause of pneumonia in this age group.
Step 3: Set aside the others. Klebsiella, H. influenzae, and Staph aureus are recognised but less common bacterial causes, while atypical pneumonia is driven by mycoplasma and chlamydia.
\[\boxed{\text{Streptococcus pneumoniae}}\]
Step 2: Name the top bacterium. Streptococcus pneumoniae (the pneumococcus) is the most frequent bacterial cause of pneumonia in this age group.
Step 3: Set aside the others. Klebsiella, H. influenzae, and Staph aureus are recognised but less common bacterial causes, while atypical pneumonia is driven by mycoplasma and chlamydia.
\[\boxed{\text{Streptococcus pneumoniae}}\]
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