Pseudomonas spp

Pseudomonas

-Genus -x- accounts for the largest percentage of all non-fermenters isoloated from clinical specimens

-Gram-negative bacilli or cocobacilli

-Strictly aerobic

-Motile (polar flagella)

-(+) Oxidase except P. luteola and P. oryzihabitans

-(+) Catalase

-Grows on MAC Agar

-Oxidizer of carbohydrates

1. pyocyanin

2. pyoverdin

3. pyorubin

4. pyomelanin

4 pigments

Pseudomonas aeruginosa

Most clinically isolated species

• Survives in nature and hospitals

• Opportunistic pathogen

• Can cause community or hospitalacquired infections• It will cause a disease or sickness to your patient, especially if the host’s immune system is immunocompromised

• Causes nosocomial infection

• Habitat or reservoir - found in the environment, in soil, water, and plants

• Survives well in domestic environments such as in hot tubs, whirlpools, contact lens solutions

• In the hospital environment, it will dwell in the sink, shower, respiratory equipment

• Rarely part of the normal flora of healthy humans

1. folliculitis

2. otitis externa

3. infection following trauma

4. osteomyelitis

5. endocarditis

6. respiratory infection

community-acquired infections of P. aeruginosa

1. bacteremia

2. UTI

hospital acquired infection of P. aeroginosa

• Exotoxin A

• Endotoxin (Lipopolysaccharide)

• Proteolytic enzymes

• Alginate

• Pili

• Motility (flagella)

Virulence factors of P. aeruginosa

Exotoxin A

most important exotoxin in P. aeruginosa and functions similar to diphtheria toxin by blocking protein synthesis

Proteolytic enzymes and hemolysines

capable of destroying cells and tissues

Alginate

polysaccharide polymer; an overproduction causes mucoid colonies and production of biofilm, therefore contributing to the infection potential of patients with cystic fibrosis

PYOVERDIN

• Yellow-green pigment

• Water-soluble ; NOT Chloroform extractable

• Fluoresces under short-wavelength ultraviolet light

PYOCYANIN

• Blue phenazine pigment

• Water-soluble ; Chloroform extractable

• Its presence can be used to specifically identify P. aeruginosa

• Produces reactive oxygen species which causes damage to cells

• The reactive oxygen species are also bacteriocidal to the organism

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

pyorubin

red pigment

pyomelanin

brown or black pigment

1. ecthyma gangernosum

2. jacuzzi/ hot tub syndrome

3. nail infection

the several diseases P. aeruginosa can cause:

ECTHYMA GANGRENOSUM

P. aeruginosa may invade and destroy the walls of the subcutaneous blood vessels, resulting in the formation of cutaneous papules that become black and necrotic

JACUZZI / HOT TUB SYNDROME

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

NAIL INFECTION

• The artificial nails, the nail beds become infected with the organism

• Can cause a greenish discolorationon the nail bed

Gram-negative bacilli or coccobacilli

Gram staining of P. aeruginosa

colorless colonies

for MacConkey agar, describe the colonies of P. aeruginosa

beta

On SBA, P. aeruginosa colonies are -x- hemolytic

flat spreading colonies

describe the colonies of P. aeruginosa on SBA

fruity grape-like odor; 2-aminoacetophenone

odor of P. aeruginosa on SBA and what causes it?

(+) Arginine dihydrolase

• (+) Citrate and Oxidase

• Dentrification of nitrates and nitrites

• Grows at 42 deg C

• Acetamide utilization

biochemical tests for P. aeruginosa

Cetramide agar

very specific agar for Pseudomonas aueroginosa; selective and differential medium for its identification; acts as a detergent and enhances production of pigments

Alkaline slant over alkaline butt, no gas, no H2S

TSI P. aeruginosa

Pseudomonas Fluorescent Group

Produces pyoverdin;

Pseudomonas aeruginosa

Pseudomonas fluorescens

Pseudomonas putida

Pseudomonas veronii

Pseudomonas monteilii

Pseudomonas mosselii

Pseudomonas Non-fluorescent Group

Pseudomonas stutzeri

Pseudomonas mendocina

Pseudomonas alcaligenes

Pseudomonas pseudoalcaligenes

Pseudomonas luteola

Pseudomonas oryzihabitans

P. aeruginosa

what pseudomonas spp grows at 42 degcel?

P. fluorescens

what Pseudomonas spp. is positive for gelatin liquefied?

Stutzeri

can grow in anaerobic environment in nitrate-containing media, which then differentiates it from other Pseudomonas

P. putida and P. fluorescens

both rarely causes clinical disease due to being of low virulence. But there are reported cases of UTI, post-surgical abscesses, emphyma, septic arthritis and other wound infections

• Both produce pyoverdin, but neither produces pyocyaninor grows at 42 deg C

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

P. putida

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

Gelatin hydrolysis

can be used to differentiate putida from fluorescens since putida (-) while fluorescens (+)

Pseudomonas oryzihabitans

• (-) Oxidase

• Found in Japanese rice paddies and has been isolated from hospital drains and respiratory therapy equipment

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

Pseudomonas luteola

• (-) Oxidase

• Recovered as the only isolated from a case of prosthetic valve endocarditis and subdiaphragmatic abscess and multiple brain abscess in a child

• Can be differentiated from oryzihabitans by the ONPG test (Onitrophenyl-beta-D-galactopyranoside) and esculin hydrolysis