Pseudomonas

aerobic

Pseudomonas is strictly?

MacConkey agar

Pseudomonas grows on what agar?

Pseudomonas luteolus and Pseudomonas orzyhabitans

Pseudomonas is oxidase positive except for?

• Pyocyanin

• Pyorubin

• Pyruvin

• Pyomelanin

Pigments produced by Pseudomonas aeruginosa

• environment (soil, water, plants)

• hot tubs, whirlpools, contact lens solutions (domestic environment)

• sink, shower, respiratory environment (hospital environment)

Habitat or reservoir of Pseudomonas aeruginosa

• Folliculitis

• Otitis externa

• Osteomyelitis

• Endocarditis

• Respiratory infection

• Bacteremia and Urinary Tract Infection (UTI)

Community acquired infections caused by P. aeruginosa

Exotoxin A

• The most important exotoxin

• blocks protein synthesis which kills the host’s cells

• Exotoxin A

• Hemolysins

• Proteases

• Lesithinase

• DNAse

• LSTase

• Deoxyribonucleases

What are the exotoxins

Endotoxin

Lipopolysaccharides

Proteolytic enzymes and hemolysins

Capable of destroying cells and tissues

Alginate

• A polysaccharide polymer

• overproduction of this causes mucoid colonies and production of biofilm

• contribute to the infection potential of patients with cystic fibrosis

• Allow the organism to inhibit phagocytosis

Pili

mediate attachment of the organism to host cells

Motility

flagella

Producing pigments

one of the identifying characteristics of Pseudomonas aeruginosa

Pyoverdin

• Is a yellow-green pigment and it is water-soluble.

• It fluoresces under short wavelength ultraviolet light.

Pyocyanin

• Blue phenazine pigment, water soluble.

• Combining with pyoverdine, it produces the characteristic green color

• Its presence can be used to specifically identify Pseudomonas aeruginosa

Catalase

In order to protect itself from destruction, the organism produces the enzyme?

Pyorubin

Is a red pigment, water soluble

Pyomelanin

A brown or black pigment, also water soluble

Eczema gangrenosum

Pseudomonas aeruginosa may invade and destroy the walls of the subcutaneous blood vessels, resulting in the formation of cutaneous papules that become black and necrotic. This condition is called?

Jacuzzi or hot tub syndrome

In swimmers and divers, a necrotizing rash develops in users in recreational facilities that are infected with the organism.

Nail infection

If the artificial nails, the nail bed becomes infected with the organism, it can cause a greenish discoloration on the nail bed.

• Sheep Blood Agar

• MacConkey agar

• Cetrimide agar

What agar is used to culture Pseudomonas aeruginosa?

Sheep Blood agar

• colonies are beta hemolytic

• Clearing of the blood and will produce flat spreading colonies

• Produces fruity grape-like odor caused by the presence of 2-aminoacetaphenol.

MacConkey agar

colorless colonies on this agar

Cetrimide agar

• A very specific agar

• a selective and differential medium for the identification of Pseudomonas aeruginosa.

• The content of this agar act as a detergent that inhibits most bacteria

• The medium also enhances the production of the pigments

42 degrees Celsius

Growth requirement of Pseudomonas aeruginosa

Alkaline slant, Alkaline but, without gas, without Hydrogen sulfide

Pseudomonas aeruginosa on Triple sugar iron agar

• Aminoglycosides

• piperacillin and ticarcillin

• 3rd and 4th generation cephalosporins (Ceftazidime and Cefepime)

• carbapenems (except ertapenem)

• fluoroquinolones

Pseudomonas aeruginosa is susceptible to?

• penicillin

• ampicillin

• first and second generation cephalosporins

• trimethoprim-sulfamethoxazole (SXT)

• Chloramphenicol

• tetracyclines

Pseudomonas aeruginosa is resistant to?

• Pseudomonas aeruginosa

• Pseudomonas fluoroscens

• Pseudomonas putida

• Pseudomonas veronii

• Pseudomonas monteilii

• Pseudomonas mosselii

Pseudomonas fluorescent group

P. putida and P. fluoroscens

• low virulence

• There are reported cases of UTI, post-surgical abscesses, empyema, septic arthritis, and other wound infections.

• Produce pyoverdine

• does not grow on 42 degrees Celsius

• cannot reduce nitrate to nitrogen gas, but they can produce acid from xylose

Gelatin hydrolysis

can be used to differentiate putida from fluoroscens, since putida is negative and fluoroscens is positive

Pseudomonas putida

Has been associated with catheter-related sepsis in patients with cancer

• Pseudomonas stutzeri

• Pseudomonas mendocina

• Pseudomonas pseudoalcaligenes

• Pseudomonas alcaligenes

• Pseudomonas luteola

• Pseudomonas oryzihabitans

Pseudomonas nonfluorescent group

Pseudomonas orzyhabitans

• Has been found in Japanese rice paddies and has been isolated form hospital drains and respiratory therapy equipment.

• has been isolated from the eye of one patient with post-operative endophthalmitis.

Pseudomonas luteola

• recovered as the only isolate from a case of prosthetic valve endocarditis and subdiaphragmatic abscess and multiple brain abscess in a child.

ONPG test and Esculin hydrolysis

P. luteola can be differentiated from P. orzyhabitans using what tests?