Chapter 20 Lower Respiratory Tract Infection

Question 1

How do invaders avoid normal defense mechanisms of the lung to cause lower respiratory tract infections?

Answer 1

• Mechanisms used to avoid phagocytosis (by bacteria)
• Capsules
• Toxins – cytotoxins, leukocidins, exotoxins
• Mechanisms used to survive in the phagocyte
• Inhibition of lysosome fusion
• Escape from phagolysosome
• Resistance to killing in phagolysosome
• Proliferation in phagocytic cell
• Non-phagocytic entry into phagocytes (direct entry into cytoplasm)