Which pathogens are commonly associated with patchy radiographic infiltrates in pneumonia?

Which pathogens are commonly associated with patchy radiographic infiltrates in pneumonia?

• A. Staph aureus, Legionella, and Mycoplasma
• B. Strep pneumoniae, H influenzae, and Klebsiella
• C. Pneumocystis jirovecii
• D. Klebsiella only

Answer: (A)

Patchy radiographic infiltrates reflect a bronchopneumonia pattern, where infection centers around bronchi and spreads to adjacent alveoli, causing multiple ill-defined spots rather than a single dense lobe. Staphylococcus aureus, Legionella, and Mycoplasma pneumoniae are classic causes of this patchy/multilobar pattern. Staph aureus frequently produces patchy infiltrates that can progress and may involve multiple lobes, especially after influenza. Legionella often presents with focal or patchy infiltrates and can accompany systemic features, not limited to one lung area. Mycoplasma pneumoniae tends to cause an atypical pneumonia with interstitial or patchy airway-centered infiltrates that are often bilateral. In contrast, pneumococcal pneumonia from Streptococcus pneumoniae typically yields a lobar consolidation rather than patchy infiltrates, Klebsiella classically causes focal lobar consolidation often with upper-lobe predilection and possible cavitation, and Pneumocystis jirovecii more characteristically shows diffuse interstitial or perihilar ground-glass–type infiltrates rather than discrete patchy consolidations.

Patchy radiographic infiltrates reflect a bronchopneumonia pattern, where infection centers around bronchi and spreads to adjacent alveoli, causing multiple ill-defined spots rather than a single dense lobe. Staphylococcus aureus, Legionella, and Mycoplasma pneumoniae are classic causes of this patchy/multilobar pattern. Staph aureus frequently produces patchy infiltrates that can progress and may involve multiple lobes, especially after influenza. Legionella often presents with focal or patchy infiltrates and can accompany systemic features, not limited to one lung area. Mycoplasma pneumoniae tends to cause an atypical pneumonia with interstitial or patchy airway-centered infiltrates that are often bilateral.

In contrast, pneumococcal pneumonia from Streptococcus pneumoniae typically yields a lobar consolidation rather than patchy infiltrates, Klebsiella classically causes focal lobar consolidation often with upper-lobe predilection and possible cavitation, and Pneumocystis jirovecii more characteristically shows diffuse interstitial or perihilar ground-glass–type infiltrates rather than discrete patchy consolidations.