Bacterial pneumonia

Bacterial (pyogenic) pneumonia is common and is a major cause of morbidity and mortality globally.

Clinical presentation

Bacterial pneumonia has symptoms similar to other pneumonia. When a productive cough is present, purulent or blood-stained sputum may indicate bacterial pneumonia .

Pathology

Bacterial pneumonia may be primary, secondary to a viral infection, or a co-infection with a virus . They are a common cause of community-acquired pneumonia (CAP) and nosocomial pneumonia.

Etiology

Typical bacteria that cause pneumonia include :

  • Streptococcus pneumoniae: most common cause of CAP
  • Streptococcus anginosus group (formerly Streptococcus milleri)
  • Staphylococcus aureus
  • group A Streptococcus
  • Klebsiella pneumonia (Klebsiella pneumonia)
  • Haemophilus influenzae (pulmonary Haemophilus influenzae infection)
  • Moraxella catarrhalis
  • anaerobes
  • Gram-negative organisms

Radiographic features

Plain radiograph / CT

Chest x-ray and CT are unable to differentiate bacterial pneumonia from non-bacterial pneumonia . There is also a large overlap of imaging features with non-pneumonic processes .

Bacterial pneumonia characteristically produces focal segmental (i.e. bronchopneumonia) or lobar pulmonary opacities (i.e. lobar pneumonia) . Expansion characterized by bulging fissures has typically been attributed to lobar pneumonia, in particular Klebsiella pneumonia, but there are many non-bacterial causes .

Treatment and prognosis

Treatment is with antibiotic therapy, with both oral and intravenous options available depending on the severity and local guidelines.

Complications

Complications common for bacterial pneumonia include :