In school-age children, which organism is commonly implicated in atypical pneumonia?

• A. Streptococcus pneumoniae
• B. Mycoplasma pneumoniae
• C. Chlamydia pneumoniae
• D. Haemophilus influenzae

Answer: (B)

Mycoplasma pneumoniae is the classic cause of atypical pneumonia in school-age children. This organism has no cell wall, which explains why it’s not seen on Gram stain and why beta-lactam antibiotics (like penicillins) often don’t work against it. Clinically, it tends to produce a slower onset with a dry, nonproductive cough, malaise, and low-grade fever, and chest imaging typically shows diffuse interstitial or patchy perihilar infiltrates rather than a single lobar consolidation. It also spreads easily in close-contact settings such as schools, leading to outbreaks. While other organisms can cause pneumonia, they usually present as typical pneumonia with higher fever and productive cough or are less common in this age group, making Mycoplasma pneumoniae the best fit for atypical pneumonia in school-age children.