TB = infection with Myobacterium tuberculosis (&other closely related myobacterial species)

Can have...

Primary TB - initial infection

Latent TB - Persistent but inactive TB (resides in macrophages)

secondary TB - reactivation

Active TB - Non latent (primary or secondary) TB

Pulmonary TB = TB of the lungs (most common site as plenty of O2)

Extra-pulmonary TB = TB outside the lungs (lymph nodes etc.)

Non-tuberculous mycobacterial (NTM) infection = other infections caused by other Mycobacterial species

Epidemiology

30% (2 billion) of the world’s population have latent TB

2 million people die from TB every year

Major morbidity & economic impacts

Aetiology

• Mycobacterium tuberculosis (& related species in the same complex)
• They have a unique cell wall, which is “waxy” & impermeable, this is why they don't stain (acid-fast), also why they are good at evading natural defences and have good resistance to antibiotics
  • Described as acid fast bacilli
• They can infect various different body tissues