PATHOGENS

Some pathogens may routinely cause lung abscesses/cavities. Lung abscesses are often polymicrobial and involve oral flora.

• Bacteria:
  • S. aureus, including MRSA and MSSA
  • Anaerobes: among the most common cause, putrid sputum is diagnostic of this class of pathogens
    • Fusobacterium nucleatum, Bacteroides melaninogenicus and Peptostreptococcus are leading anaerobic pathogens.
  • Aerobic and microaerophilic streptococci, including S. anginosusgroup and Group A streptococci.
  • Gram-negative bacteria, especially in Taiwan, an unexplained strong association with Klebsiella pneumoniae
    • Also, P. aeruginosa.
    • Meloidosis (Burkholderia pseudomallei) is a concern, especially in SE Asia.
  • Legionella
  • Nocardia
  • Actinomyces
  • Group A streptococci
  • H. influenzae (type b)
  • Rhodococcus equi
• Mycobacteria: M. tuberculosis, MAI, M. kansasii, M. abscessus
  • Also, almost any non-tubercular mycobacteria may produce an abscess/cavity.
• Fungi: Aspergillus, Cryptococcus, Coccidioides, Histoplasma, Blastomyces, Fusarium, Mucor, Rhizopus
• Parasitic: usually more cystic
  • Hydatid cysts (Echinococcus)
  • Paragonimiasis