Pseudomonas + related organisms

Question 1

What is the main distinguishing factor between the gram negative, non-glucose fermenting bacilli?

Answer 1

oxidase
(+): pseudomonas and burkholderia
(-): Acinteobacter baumannii and Stenotrophomonas maltophilia

Question 2

What is the most common cause of ventilator-associated pneumonia?

Answer 2

Pseudomonas aeruginosa

Question 3

What is ecthyma gangrenosum?

Answer 3

A well-recognized but uncommon cutaneous infection most often associated with Pseudomonas aeruginosa bacteremia; usually occurs in patients who are critically ill and/or immunocompromised.

Question 4

Describe the characteristic lesions associated with ecthyma gangrenosum.

Answer 4

hemorrhagic pustules or infarcted-appearing areas with surrounding erythema that evolve into necrotic ulcers surrounded by erythema.

Question 5

What is the best treatment for pseudomonas aeruginosa?

Answer 5

combination therapy (due to resistance to several of the common antibiotics)

Question 6

List the main Burkholderia species we talked about.

Answer 6

-Burkholderia pseudomallei
-Burkholderia cepacia
(belong to same genomospecies, so highly related)

Question 7

What are the different phases of Melioidosis?

Answer 7

• Acute: septicemia w/ metastatic lesions, 95% mortality if untreated
• Subacute: TB-like pneumonia w/ cellulitis and lymphangitis, most common
• Chronic: localized chronic cellulitis, treat w/ abx before draining otherwise may become bacteremic

Question 8

What is an important piece of information to remember when treating Stenotrophomonas maltophilia?

Answer 8

It is a multi-drug resistant organism that is intrinsically resistant to carbapenems.