MICROBIOLOGY

• C. pneumoniae is an obligate intracellular Gram-negative bacterium.
  • It grows like a virus (requires cell culture systems) but is a bacterium with RNA and DNA.
  • An intracellular organism parasite requires a host cell for ATP/GTP.
  • Known to also cause disease in koalas, reptiles and amphibians.
• The elementary body is metabolically inactive and has a rigid cell wall that permits survival outside the cell and is infectious [Fig]. Inside the cell, it is seen as a reticulate body that is metabolically active but non-infectious.
• Incubation culture to positivity: average 21 d.
• Historically known as the "TWAR" agent, two of the original isolates were from Taiwan.
  • Formerly called Chalmydophila pneumoniae.