UPSC-CMS 2019 — Microbiology

Question 1: The most common organism causing Acute Otitis media in children is:

• A. Staphylococcus epidermidis
• B. Streptococcus pneumoniae (Correct Answer)
• C. Klebsiella pneumoniae
• D. Escherichia coli

Explanation: ***Streptococcus pneumoniae*** - **_Streptococcus pneumoniae_** is the most frequent bacterial cause of **acute otitis media (AOM)** in children, accounting for a significant percentage of cases. - Its presence often leads to **inflammation** and **fluid accumulation** in the middle ear, characteristic of AOM. *Staphylococcus epidermidis* - While **_Staphylococcus epidermidis_** is a common **skin commensal** and a frequent cause of device-related infections, it is rarely implicated in acute otitis media. - Its role in AOM is usually limited to **contaminant cultures** rather than true infection. *Klebsiella pneumoniae* - **_Klebsiella pneumoniae_** is more commonly associated with **pneumonia**, **urinary tract infections**, and **healthcare-associated infections**, particularly in immunocompromised individuals. - It is an **uncommon cause** of typical acute otitis media in healthy children. *Escherichia coli* - **_Escherichia coli_** is a common cause of **urinary tract infections** and **gastrointestinal infections**. - It is **rarely a primary cause** of acute otitis media, especially in otherwise healthy children, unless there are underlying risk factors or specific infection pathways.