bacterial pneumonia I (5)

Question 1

which pseudomonias is considered “serious in the context of CF”?

Answer 1

B. cepacia

Question 2

what pseudomonias is considered “common and a serious nosocomial pathogen”

Answer 2

P. aeruginosa

Question 3

what pseudomonias grows green in culture? why?

Answer 3

P. aeruginoas because it produces pyocyanin

Question 4

describe the bacteriology of the pseudomonias
gram
aerobes?
fermenters?
oxidase?
culturable?

Answer 4

gram -
non fermenters
oxidase +
grow easily in culture

Question 5

why are the pseudomonas (besides P. aeruginosa) extremely antibiotic resistant?

Answer 5

due to combo of low permeability outer membrane and efflux pumps

Question 6

what two pseudomonias have very minimal growth requirements?

Answer 6

P. aeruginosa and B. cepacia

Question 7

what are the 4 community acquired presentations of P. aeruginosa?

Answer 7

1. endocarditis in drug addicts
2. otitis externa in chlorinated hot tubes
3. osteochondritis in sneaker punctures
4. corneal infections under contact lens

Question 8

where is the most likely place for disease presentation with P. aeruginosa?

Answer 8

hospital

Question 9

where is the most likely place for disease presentation with B. cepacia?

Answer 9

CF center

Question 10

where is the most likely place for disease presentation with B. pseudomallei?

Answer 10

previously ill travelers/immigrants or vietnam veterans

Question 11

where is the most likely place for disease presentation with B. mallei?

Answer 11

previously ill travelers/immigrants with animal handling hx

Question 12

why must you treat chlamydia with drugs that can penetrate the human cell membrane

Answer 12

bc it is obligate intracellular

Question 13

briefly explain the “unique manner” in which chlamydia replicates

Answer 13

beginning with tiny, infectious, rugged, elementary bodies which “unpack” into reticulate bodies after infection
Reticulate bodies form intracellular inclusions (visible on microscopy) within the inclusions they multiply by binary fission, forming new reticulate bodies and later new elementary bodies.

Question 14

what 3 types of chlamydia cause pneumonia

Answer 14

C. pneumoniae
C. psittaci
C. trachomatis

Question 15

how do you treat chlamydia

Answer 15

tetracyclines (doxy) except prego/peds/allergic who get erythromycin (or alternatives)

Question 16

how is C. psittaci transmitted

Answer 16

via infected birds to humans through respiratory route through direct contact or aerosoliazation

Question 17

which chlamydia do you see horder spots? what are these spots

Answer 17

C. psittaci

erythematous. blanching, maculopapular rash

Question 18

what is a known virulence factor of chlamydia? what is its function

Answer 18

T3SS used for entry and establishing inclusion bodies

Question 19

list some of the virulence factors of P. aeruginosa (5)

Answer 19

1. endotoxin- cell wall component that causes sepsis
2. exotoxin- T3SS and exoS will damage cytoskeleton
3. enzymes- elastase, protease, histotoxic-all facilitate invasion of the blood stream
4. pyocyanin-interferes with ETC
5. glycocalyx- antiphagocytic
6. efflux pumps

Question 20

how will P. aeruginosa appear on triple sugar iron agar

Answer 20

as a metallic sheen

Question 21

what is the reservoir for pseudomonad pathogens?

Answer 21

envirnmental
P. aeruginosa can also be in normal skin flora
B. mallei is in live stock

Question 22

what are the 3 virulence factors of B. cepacia? what do they do?

Answer 22

lipase, metalloproteases, serine proteases

^all destroy tissue

Question 23

what are the virulence factors for B. pseudomallei?

Answer 23

capsule-resists endocytosis, enhances spread, adhesions, fimbriae bind to cells