Pseudomonas aeruginosa

Question 1

Characteristics of Pseudomonas aeruginosa

Answer 1

G - 
rod
NON fermenter
motile w/ flagella
aerobic
simple growth requirement

Question 2

ID pseudomonas

Answer 2

McConkey agar

electron micrograph

Question 3

Major characteristic of PA

Answer 3

Biofilms

Question 4

How do biofilms cause chronic infections

Answer 4

restant to antibiotics - exopolysaccharide matrix enclosed bacterial community

Question 5

Which disease is biofilm formation seen in?

Answer 5

Cystic fibrosis

Question 6

Virulence factors

Pseudomonas aeruginosa

Answer 6

• Exotoxin A: ADP ribosylation of EFII
• Exoenzyme S: for dissemination from burn wounds, tissue destruction in lung infections. Type III secretion system
• Elastase: complement comp breakdown, controlled by LasR “quorum sensing”. Iron regulated
• PLC and heat stable Phospholipase: hydrolysis
• Alkaline phosphatase: proteolysis
• Alginate : promotes adherence, interferes w phagocytosis

Question 7

What is a predisposing factor for septicemia

Answer 7

neutropenia, burns

Question 8

What can cause pseudomonas folliculitis

Answer 8

contaminated water, hair depilation, fingernail infection

Question 9

What is the result of PA bacteremia in neutropenic patients

Answer 9

Ecthyma gangrenosa

Question 10

Cystic fibrosis - PA - chest x ray would show what

Answer 10

bilateral bronchopnuemonia

Question 11

Contact lenses and PA infection

Answer 11

hemolysin (beta hemolytic)
difficult to treat

more susceptible if the eye is scratched

Question 12

Treatment for P. aeruginosa

Answer 12

Resistant to many Abx

Use combination therapy: Anti-psudomonas: penicillin, ticarcillin, or piperacillin
PLUS AMG - gentamicin, amikacin

Question 13

CF info

Answer 13

AR
homozygotes
chrmsm 7
CFTR

underlying compromised condition

Question 14

What is the mutation in CFTR

Answer 14

three nucleotide deletion causing deletion of a single AA, deltaF508

Question 15

Organs affected by CF

Answer 15

lung, exocrine glands (pancreas and SI)

Question 16

What is typically seen CF patients

Answer 16

pancreatic insufficiency, with 15% of them suffering from intestinal blockage (Meconium ileus)

Question 17

Three pathogens that colonize CF lung:

which ones colonize initially? later on?

Answer 17

S. aureus - initial
H. influenza - initial
P. aeruginosa - later on becomes main one

Question 18

Clinical manifestation of CF

Answer 18

localized lung infection - excessive neutrophil infiltration

malnutrition

Question 19

where is the CF infection confined?

Answer 19

to and around bronchi and bronchioles

Question 20

CF phenotype of PA

Answer 20

Biofilm
Mucoid
Rough LPS
Serum sensitive
Low toxigenicity (to co-exist with the host)

Question 21

What makes up the alginate?

Answer 21

D-Mannuronic acid
L-Guluronic acid

(polymer)

Question 22

PA infection in CF lung is chronic. Why type of hypersensitivity?

Answer 22

Type III

Question 23

What is a frustrated phagocyte seen in CF?

Answer 23

large target, neutrophil not able to extend enough for engulfment

Question 24

Why is transplantation in CF patients not the best solution for the patient?

Answer 24

Genetic condition (already a problem) + need for immunosuppresants –> cause more infections