Pseudomonas aeruginosa Flashcards
Characteristics of Pseudomonas aeruginosa
G - rod NON fermenter motile w/ flagella aerobic simple growth requirement
ID pseudomonas
McConkey agar
electron micrograph
Major characteristic of PA
Biofilms
How do biofilms cause chronic infections
restant to antibiotics - exopolysaccharide matrix enclosed bacterial community
Which disease is biofilm formation seen in?
Cystic fibrosis
Virulence factors
Pseudomonas aeruginosa
- 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
What is a predisposing factor for septicemia
neutropenia, burns
What can cause pseudomonas folliculitis
contaminated water, hair depilation, fingernail infection
What is the result of PA bacteremia in neutropenic patients
Ecthyma gangrenosa
Cystic fibrosis - PA - chest x ray would show what
bilateral bronchopnuemonia
Contact lenses and PA infection
hemolysin (beta hemolytic)
difficult to treat
more susceptible if the eye is scratched
Treatment for P. aeruginosa
Resistant to many Abx
Use combination therapy: Anti-psudomonas: penicillin, ticarcillin, or piperacillin
PLUS AMG - gentamicin, amikacin
CF info
AR
homozygotes
chrmsm 7
CFTR
underlying compromised condition
What is the mutation in CFTR
three nucleotide deletion causing deletion of a single AA, deltaF508
Organs affected by CF
lung, exocrine glands (pancreas and SI)
What is typically seen CF patients
pancreatic insufficiency, with 15% of them suffering from intestinal blockage (Meconium ileus)
Three pathogens that colonize CF lung:
which ones colonize initially? later on?
S. aureus - initial
H. influenza - initial
P. aeruginosa - later on becomes main one
Clinical manifestation of CF
localized lung infection - excessive neutrophil infiltration
malnutrition
where is the CF infection confined?
to and around bronchi and bronchioles
CF phenotype of PA
Biofilm Mucoid Rough LPS Serum sensitive Low toxigenicity (to co-exist with the host)
What makes up the alginate?
D-Mannuronic acid
L-Guluronic acid
(polymer)
PA infection in CF lung is chronic. Why type of hypersensitivity?
Type III
What is a frustrated phagocyte seen in CF?
large target, neutrophil not able to extend enough for engulfment
Why is transplantation in CF patients not the best solution for the patient?
Genetic condition (already a problem) + need for immunosuppresants –> cause more infections
