1. What is the causative agent for general population CAP?
Answer: Community-Acquired Pneumonia in the general population is most
commonly caused by Streptococcus pneumoniae.
Explanation: S. pneumoniae is the leading bacterial cause of CAP because it
commonly colonizes the respiratory tract and can invade lung tissue.
2. What is the causative agent for smokers and COPD CAP?
Answer: Haemophilus influenzae infection.
Explanation: Smokers and patients with Chronic Obstructive Pulmonary Disease have
impaired airway defenses, making H. influenzae a common cause.
3. What is the causative agent for CF CAP?
Answer: Pseudomonas aeruginosa infection.
Explanation: Patients with Cystic Fibrosis are highly susceptible to chronic
Pseudomonas lung infections.
4. What is the causative agent for atypical CAP?
Answer: Mycoplasma pneumoniae infection.
Explanation: Mycoplasma causes “walking pneumonia” and does not have a cell wall,
making beta-lactam antibiotics ineffective.
5. What are the first line treatment options for CAP?
Answer: Amoxicillin or a macrolide such as Azithromycin.
Explanation: These medications cover the most common CAP pathogens in otherwise
healthy outpatients.
6. Which is the gold standard diagnostic test for CAP?
Answer: Chest X-ray.
Explanation: A chest radiograph confirms lung infiltrates consistent with pneumonia.
7. When is it appropriate to prescribe a Fluoroquinolone for CAP?
Answer: In patients with significant comorbidities, recent antibiotic use, or treatment
failure.
Answer: Community-Acquired Pneumonia in the general population is most
commonly caused by Streptococcus pneumoniae.
Explanation: S. pneumoniae is the leading bacterial cause of CAP because it
commonly colonizes the respiratory tract and can invade lung tissue.
2. What is the causative agent for smokers and COPD CAP?
Answer: Haemophilus influenzae infection.
Explanation: Smokers and patients with Chronic Obstructive Pulmonary Disease have
impaired airway defenses, making H. influenzae a common cause.
3. What is the causative agent for CF CAP?
Answer: Pseudomonas aeruginosa infection.
Explanation: Patients with Cystic Fibrosis are highly susceptible to chronic
Pseudomonas lung infections.
4. What is the causative agent for atypical CAP?
Answer: Mycoplasma pneumoniae infection.
Explanation: Mycoplasma causes “walking pneumonia” and does not have a cell wall,
making beta-lactam antibiotics ineffective.
5. What are the first line treatment options for CAP?
Answer: Amoxicillin or a macrolide such as Azithromycin.
Explanation: These medications cover the most common CAP pathogens in otherwise
healthy outpatients.
6. Which is the gold standard diagnostic test for CAP?
Answer: Chest X-ray.
Explanation: A chest radiograph confirms lung infiltrates consistent with pneumonia.
7. When is it appropriate to prescribe a Fluoroquinolone for CAP?
Answer: In patients with significant comorbidities, recent antibiotic use, or treatment
failure.
