Microbiology of Pneumonia

Question 1

What two organisms are causes of lobar pneumonia?

Answer 1

Streptococcus pneumoniae and Klebsiella pneumoniae

Question 2

What is the most common cause of community acquired pneumonia and secondary pneumonia?

Answer 2

Streptococcus pneumoniae

Question 3

Which organism is associated with enteric flora that is aspirated and affects malnourished and debilitated individuals?

Answer 3

Klebsiella pneumoniae

Question 4

What is a common cause of secondary pneumonia and pneumonia superimposed on COPD?

Answer 4

Haemophilus influenzae

Question 5

What causes pneumonia in cystic fibrosis patients?

Answer 5

Pseudomonas aeruginosa

Question 6

What is a common cause of community acquired pneumonia and pneumonia superimposed on COPD?

Answer 6

Moraxella catarrhalis

Question 7

Which organism is best visualized by silver stain and is associated with pneumonia in immunocompromised patients or community acquired pneumonia or pneumonia superimposed on COPD?

Answer 7

Legionella pneumophila

Question 8

What is the most common cause of atypical pneumonia in infants?

Answer 8

Respiratory syncytial virus (RSV)

Question 9

What is the most common cause of atypical pneumonia with posttransplant immunosuppressive therapy?

Answer 9

CMV

Question 10

What is the most common cause of atypical pneumonia in elderly, immunocompromised, and those with preexisting lung disease? What does it increase the risk of?

Answer 10

Influenza virus. S aureus or H infleunzae bacterial pneumonia.

Question 11

What is the most common cause of atypical pneumonia? Who does it affect? What are the complications? Is it visible on gram stain?

Answer 11

Mycoplasma pneumoniae. Usually affects young adults (classically, military recruits or college doem students). Complications include autoimmune hemolytic anemia (IgM against I antigen on RBCs causes cold hemolytic anemia) and erythema multiforme. Not visible on gram stain due to lack of cell wall.

Question 12

What is the most common cause of atypical pneumonia? Who does it affect? What are the complications? Is it visible on gram stain?

Answer 12

Mycoplasma pneumoniae. Usually affects young adults (classically, military recruits or college doem students). Complications include autoimmune hemolytic anemia (IgM against I antigen on RBCs causes cold hemolytic anemia) and erythema multiforme. Not visible on gram stain due to lack of cell wall.

Question 13

What is the second most common cause of atypical pneumonia in young adults?

Answer 13

Chlamydia pneumoniae

Question 14

What is the most common cause of atypical pneumonia with high fever (Q fecer) and seen in farmers and veterinarians? How is it transmitted?

Answer 14

Coxiella burnetii. Spores are deposited on cattle by ticks or are present in cattle placentas.

Question 15

How is Coxiella burnetii different from other rickettsiae despite being one itself?

Answer 15

1. Causes pneumonia
2. Does not require arthropod vector for transmission (uses highly heat-resistant endospores)
3. does not produce a skin rash