36. Which one of the following organisms is most likely to be the cause of pneumonia in an
immunocompetent infant?
1. Nocardia asteroids
2. Serratia marcescens
3. Mycoplasma pneumonia
4. Legionella pneumophila

Pneumonia in Immunocompetent Infants: Causes, Symptoms, and Treatment

Pneumonia is a significant respiratory infection that affects individuals of all ages, including infants. Identifying the most common causative agent is crucial for effective treatment. Among the given options, the most likely cause of pneumonia in an immunocompetent infant is Mycoplasma pneumoniae.

Correct Answer: 3. Mycoplasma pneumoniae

Why Mycoplasma pneumoniae Causes Pneumonia in Infants?

Mycoplasma pneumoniae is a common bacterial pathogen that causes atypical pneumonia in children and young adults. Unlike other bacterial infections, it lacks a cell wall, making it resistant to beta-lactam antibiotics. This organism spreads through respiratory droplets and primarily affects the upper and lower respiratory tracts.

Comparison with Other Options

Thus, Mycoplasma pneumoniae remains the most likely pathogen for pneumonia in an immunocompetent infant.

Symptoms of Mycoplasma Pneumonia in Infants

Infants infected with Mycoplasma pneumoniae may exhibit the following symptoms:

• Persistent cough
• Fever
• Difficulty breathing
• Wheezing or crackling sounds in the lungs
• Fatigue and irritability

How Pneumonia is Diagnosed?

Diagnosis of Mycoplasma pneumoniae is performed using:

• Chest X-ray: Shows diffuse or patchy infiltrates.
• Serology Tests: Detect IgM and IgG antibodies.
• PCR (Polymerase Chain Reaction): Confirms bacterial DNA presence.

Treatment and Management

Since Mycoplasma pneumoniae lacks a cell wall, beta-lactam antibiotics (like penicillin) are ineffective. The treatment includes:

• Macrolide Antibiotics: Azithromycin or erythromycin.
• Supportive Care: Hydration and oxygen therapy if needed.
• Symptom Management: Fever control with acetaminophen.

Preventive Measures

• Regular hand hygiene to reduce transmission.
• Avoiding close contact with infected individuals.
• Maintaining good respiratory hygiene.

Conclusion

Mycoplasma pneumoniae is the most probable cause of pneumonia in immunocompetent infants. Early diagnosis and appropriate antibiotic treatment ensure better recovery. Awareness about symptoms and preventive measures can help in reducing the spread of this infection.

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