Which pathogens are most commonly implicated in community-acquired pneumonia in adults, and what are the nursing implications for empiric therapy?

• A. Streptococcus pneumoniae is not a common cause; atypicals and Haemophilus influenzae predominate.
• B. Streptococcus pneumoniae remains the most common cause; atypicals (Mycoplasma, Chlamydophila), Haemophilus influenzae; nursing implications: monitor response, ensure adherence, assess adverse effects, educate on vaccination.
• C. Legionella is the most common.
• D. Klebsiella is the most common.

Answer: (B)

Streptococcus pneumoniae remains the most common cause of community-acquired pneumonia in adults, and empiric therapy should cover both typical bacteria and atypical pathogens such as Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Haemophilus influenzae. This means the chosen treatment approach targets a broad range of organisms likely to be involved, rather than focusing on less common culprits like Legionella or Klebsiella in typical outpatient CAP.

From a nursing perspective, the emphasis is on safe and effective implementation of empiric therapy. Monitor the patient closely for clinical improvement—fever resolution, symptom relief, and improved oxygenation—and be prepared to reassess if there’s no meaningful progress within 48 to 72 hours. Ensure the patient understands and adheres to the prescribed antibiotic regimen, since completing therapy helps prevent relapse and resistance. Assess for adverse effects such as gastrointestinal upset, rash, or signs of drug intolerance, and educate the patient on what to report (e.g., severe diarrhea, allergic reactions, or chest symptoms). Also reinforce preventive strategies, including vaccination against pneumococcus and annual influenza vaccination, to reduce future risk of CAP.