Pseudomonas Aeruginosa

Question 1

Are they motile? Spore forming?

Answer 1

They are non-motile and nonspore forming

Question 2

Why they do not belong to the Enterobacteriaceae?

Answer 2

They are oxidase positive and they do not ferment glucose

Question 3

How are they transmitted?

Answer 3

• In the hospital, nosocomial infections

- From the environment in soil and water like in swimming pool

Question 4

Which individuals this pathogen affects?

Answer 4

Since it is an opportunistic pathogen, it affects mostly cancer patients, those who have undergone an immunosuppressive therapy either from endogenous source or from the hospital

Question 5

What are their structural components considered as virulence factors?

Answer 5

Capsule
Pili
LPS
Pyocyanin

Question 6

From what is composed of the capsule? What is its function?

Answer 6

It is composed of a mucoid exopolysaccharide

It’s inhibits antibiotic killing come on suppressors neutrophil and lymphocyte activity

Question 7

What’s the function of the pili?

Answer 7

For adhesion

Question 8

What does the pyocyanin?

Answer 8

It impairs ciliary function, stimulates inflammatory response, mediate tissue damage through production of toxic oxygen radicals i.e. hydrogen peroxide, superoxide, hydroxyl radicals

Question 9

Which toxins and enzymes are produced by this bacteria?

Answer 9

Exotoxin A
Exotoxin S
Cytotoxin
Elastase 
Alkaline protease
Phospholipase C
Rhamnolipid
Antibiotic resistance

Question 10

What is the role of the exotoxin A and S?

Answer 10

The exotoxin A inhibits protein synthesis, produces tissue damage like in skin and cornea, is immunosuppressive

The exotoxin S inhibits protein synthesis and is immunosuppressive

Question 11

What does the cytotoxin?

Answer 11

It is cytotoxic for eukaryotic membranes e.g. disrupts leukocytes function, produces pulmonary microvascular injury

Question 12

What does the elastase?

Answer 12

It destroys elastin-containing tissues (e.g. blood vessels, lung tissue, skin), collagen, immunoglobulins and complement factors

Question 13

What does the alkaline protease?

Answer 13

It destroys tissues, and inactivates interferons and tumor necrosis factor alpha

Question 14

What is the phospholipase C? What is its function?

Answer 14

It is a heat labile hemolysin

It mediates tissue damage and stimulates inflammatory response

Question 15

What is the rhamnolipid? What is its function?

Answer 15

It is a heat stable hemolysin

It disrupts lecithin-containing tissue and inhibits pulmonary ciliary activity

Question 16

Why they are considered as highly invasive?

Answer 16

Because of the important activity of the LPS leading to septic shock and the production of several types of toxins

Question 17

In which patient the capsule has an important effect?

Answer 17

In patients with cystic fibrosis because they have excess mucus production

Question 18

Which pigments do they produce?

What is the color of each one?

Answer 18

pyoverdine: green
pyocyanin: blue green
pyorubin: red
pyomelanin: black

Question 19

To which toxin the exotoxin A is similar?

Answer 19

It is similar to the diphtheria toxin

Question 20

Where do they cause disease?

Do you what are related the disease manifestations?

Answer 20

They can cause disease in whatever organ they are introduced

Where and how bacteria are introduced

Question 21

Which organs are affected when bacteria is inserted through a catheter? Respirator? Lumbar puncture? Contact lenses or eye surgery? If it is a burned patient? From swimming pool?

Answer 21

Urinary tract, heart
Lungs leading to pneumonia
Meningitis
Manifestations vary from scarification of the cornea to complete blindness
There is a systemic spread that leads to septic shock that causes death
Otitis externa and can progress in the case of background diseases to a malignant otitis externa

Question 22

What is the typical skin manifestation that appears during septicemia caused by Pseudomonas only?

Answer 22

Ecthyma gangrenosum

It’s a necrotic skin lesion with erythematous border, nearly black colored without abscess

Question 23

What are the specimen is they can always from the blood?

Which specimen is taken in the case of pneumonia?

Answer 23

Since after the local infection there is invasiveness and spread
Sputum

Question 24

Are they gram negative or positive?

Answer 24

Gram negative coccobacilli

Question 25

Do they grow on a specific medium?

Answer 25

They grow on any medium

Question 26

How do we know in the case of burned patients that it is an infection by Pseudomonas?

Answer 26

From the skin color

Question 27

Which antibiotics are given?

Is there any vaccine?

Answer 27

Anti-pseudomonal penicillin e.g. piperacillin, mezlocillin, with aminoglycosides like gentamicin and tobramycin
Third and Fourth generations cephalosporin work against Pseudomonas, in addition to imipenem, carbapenem.
There is no vaccine.