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1
Q

what are the four pseudomonas pathogens? how common are they?

A

P aeruginosa (common and serious nosocomial pathogen), B cepacia (common and serious in context of CF), B pseudomallei and b mallei (rare in US but can be lethal)

2
Q

what is the morphology, metabolism, oxidase testing and culturability of the pseudomonas strains?

A

all gram negative, strict aerobes, nonfermenters, oxidase positive and grow easily in culture.

3
Q

what does P aerginosa look like in culture?

A

it produces green pyocyanin

4
Q

describe the antibiotic resistance in the pseudomonads.

A

all have extreme antibiotic resistance except for P aeruginosa. It is caused by low permeability outer membrane and efflux pumps denying the AB access.

5
Q

which of the pseudomonads are the easiest to grow? what is the consequence of this?

A

P aeruginosa and B cepacia have minimal growth requirements and can contaminate hospital solutions

6
Q

what community acquired presentations does P aeruginosa demonstrate?

A

endocarditis in IV drug addicts, Otitis externa in underchlorinated hot tubs, oseteochondritis in sneaker punctures and corneal infections under contact lenses

7
Q

where are the most common presentations for serious disease with P aeruginosa?

A

hospitals

8
Q

where are the most common presentations for serious disease with B cepacia?

A

in CF centers

9
Q

what are the most common presentations for serious disease with B pseudomallei?

A

in previously ill travelers/immigrants or vietnam veterans

10
Q

what are the most common presentations for serious disease with B mallei?

A

in previously ill travelers/ immigrants with animal handling history

11
Q

what is the poor prognosis presentation of the pseudomonads?

A

septicemia/pneumonia

12
Q

how are pseudomonads diagnosed and treated?

A

diagnosed by culture and gram stain

treat with combinations of antibiotics while testing for antibiotic sensitivity both before and during treatment

13
Q

describe the morphology and growth of chlamydia? what implication does this have on antibiotic use?

A

small obligate intracellular bacterium

drugs must penetrate the human cell membrane.

14
Q

what is the life cycle of Chlamydia?

A

they begin with small infectious elementary bodies that unpack into reticulate bodies after infection (visible on microscopy). they then multiply by binary fission and form new RB and later EB

15
Q

what is the known virulence factor for Chlamydia?

A

T3SS that helps the EB enter and establish itself in inclusion bodies

16
Q

what chlamydia strains can cause pneumonia?

A

C pneumonia, C psittaci and C trachomatis

17
Q

what is the basis of treatment for most chlamydia infections? in what situations is it different?

A

often initiated based on physical findings. additional diagnostics for C trachomatis in rape victims (tissue culture) or to differentiate pneumonias (serology or microimmunofluorescence)

18
Q

how are chlamydia pneumonias treated?

A

with tetracyclines except for pregnant/peds/allergic patients that get erythromycin or other alternatives. these patients may need follow up testing and retreatment