Scientific classification

Kingdom: Bacteria

Phylum: Proteobacteria

Class: Gamma Proteobacteria

Order: Pseudomonadales

Family: Pseudomonadaceae

Genus: Pseudomonas

Species: P. aeruginosa

Binomial name

Pseudomonas aeruginosa

Pseudomonas Infections

Survive where most organisms cannot; e.g., “oil-eating” bacteria are Pseudomonas.

(Slime layer)

Opportunistic pathogen

Flagella

Pseudomonas aeruginosa

Structure

1.Exotoxin A Similar in structure to Diptheria toxin Causes Dermatonecrosis in burn

wounds, corneal damage in ocular infections, and tissue damage in chronic pulmonary infections.

Also this toxin is immunosuppressive

Heat labile hemolysinBreaks down lipids and lecithin causing tissue destructionStimulates inflammatory response

2.Phospholipase C

3.Elastase and Alkaline Protease

• Destruction of elastin-containing tissues (blood vessels, lung tissue, skin), collagen, immunoglobulins, and complement factors

• Can produce hemorrhagic lesions (ecthyma gangrenosum)

• Inactivation of interferon

Clinical Disease� Pulmonary Infections

� Burn Wound Infections and other skin and soft tissue infections (life threatening)

� UTI’s (especially catheterized)

� External Otitis (malignant OE, swimmer’s ear)

� Eye Infections and corneal ulceration via contaminated contact lens cleaning fluids

� Pseudomonal Endocarditis

� Grow on most laboratory media� Blood agar � MacConkey’s agar � Minimal nutritional reqts.;

Many organic compounds used as C and N sources, but only a few carbohydrates by oxidative metabolism

� tolerate broad temperature spectrum

� its ability to grow at 42° C.

Isolation and identification

Motility of organism

Colony characteristic:

Characteristic grape-like odor and blue-green pus & colon Lactose negative on MacConkey’s agar Some strains produce diffusible pigments: Pyocyanin (blue); Fluorescein (yellow); Pyorubin (red) Fluorescence is helpful in early identification

CharacteristicsCharacteristicsBiochemical test:inability to ferment lactose,oxidase & catalase positiveNitrate reduction negative

Catalase test

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