Pulmonary Infections with G- Bacteria

Question 1

Necrotizing Lobar Pneumonia

Answer 1

• Klebsiella and enterobacter (short, encapsulated G- bacilli)
• cause nosocomial infections (pneumonia and UTI)
• multiply in alveolar spaces, exudate accumulates and walls become necrotic
• thick mucoid sputum
• tx: aggressive abx

Question 2

Legionella

Answer 2

• L. pneumophila, aerobic G- bacillus
• present in fresh water, NOT normal flora
• infection with inhaled aerosols
• Pontiac fever - flu-like illness, no pulmonary consolidation
• pneumonia - phagocytosis by alveolar macrophages but bacteria block fusion with lysosomes and proliferate
• tx: macrolide abx

Question 3

Pseudomonas aeruginosa

Answer 3

• aerobic G- rod
• Abx resistant opportunistic pathogen
• predisposition to burns, catheter, cystic fibrosis, diabetes, neutropenia
• produces vascular thrombosis and hemorrhagic necrosis in lungs and skin
• skin lesions called ecthyma gangrenosum
• can progress very rapidly to sepsis

Question 4

Melioidosis

Answer 4

• Burkholderia pseudomallei, G- bacillus in soil
• pulmonary infection ranging from mild tracheobronchitis to cavitary pneumonia
• causes discrete abscesses throughout the body
• can occur chronically and be mistaken for TB