Lower Respiratory Tract Infections

Question 1

Community-acquired PNA pathogens

Answer 1

#1: Strep. pneumoniae
H. influenzae
Anaerobes 
Legionella
Viruses

Question 2

Hospital-acquired PNA pathogens

Answer 2

GN rods:
Staph. aureus (often penicillin resistant)
klebsiella
E.coli
Pseudomonas aeruginosa

Question 3

Aspiration PNA

Answer 3

seen in pt at risk for aspiration such as alcoholics, comatose pts.
Due to anaerobic flora in oropharynx.
Klebsiella seen in alcoholics, thick capsule makes very thick viscous sputum.

Question 4

Chronic PNA pathogens

Answer 4

actinomyces, nocardia, TB, and fungi (coccidio/histo/blasto)

Question 5

PNA in Immunocompromised host; common pathogens:

Answer 5

CMV, PJP, Aspergillosis (invasive) and candidiasis

Question 6

Strep. pneumoniae

Answer 6

most common cause of community-acquired PNA (CAP)

Question 7

H. influenza

Answer 7

a common cause of CAP, often associated with COPD and causes life-threatening illness in young children.

Question 8

Staph. aureus

Answer 8

Important cause of secondary bacterial PNA (CAP), following the flu or measles, also see in IV drug users, can lead to lung abscesses.

Question 9

Klebsiella pneumoniae

Answer 9

enteric flora that is aspirated; common cause of aspiration PNA seen in debilitated, malnourished ppl, esp. alcoholics; thick capsule leads to very thick, viscous sputum.

Question 10

Pseudomonas aeruginosa

Answer 10

Common cause of bronchopneumonia in CF pts, seen as well in neutropenic patients

Question 11

Legionella pneumophila

Answer 11

Lives in artificial water sources (water tanks); gives rise to epidemic and sporadic forms of PNA (CAP); often affects immunocompromised or post-transplant pts

Question 12

community-acquired ATYPICAL pneumonia

Answer 12

mycoplasma pneumoniae (most common), RSV, CMV, influenza virus, chlamydia pneumoniae

Atypical bc moderate sputum, low fever (mild upper resp sxs)

Question 13

Mycoplasma pneumoniae

Answer 13

most common cause of community-acquired atypical PNA; seen esp. in children/young adults (in schools, prisons); member class mollicutes, smallest known free-living microorganism, no cell wall.