PSEUDOMONAS SPECIES

(pseudomonas species) Mode of transmission,mechanisms by which microorganisms cause disease and diagnosis

Define pseudomonas

  

A Gram negative rod.Its an enterobactericeae

 List the species of medical importance 

• Pseudomonas pseudomallei
• Pseudomonas aeruginosa
• Pseudomonas mutlophilia

 Mention the species of medical importance

Pseudomonas aeruginosa

Describe the normal habitat

• Pseudomonas species can be found in water, soil sewage and vegetation. They can also be found in the intestinal tract.
• Pseudomonas aeruginosa is frequently present in hospital environments especially in moist places such as sinks, bowls, drains, cleaning buckets and humidifiers. It can also be found growing in eye drops, ointments and weak antiseptic solutions
• Pseudomonas pseudomalleiis naturally found in rice paddy fields, the mud of riverbanks and surface stagnant water. The organism can infect cattle, pigs and other animals.

Describe the morphology Pseudomonas aeruginosa

• Gram negative rods
• Are motile by polar flagellum
• Non-capsulated

 Describe the mode of transmission and pathogenicity of Pseudomonas aeruginosa

TRANSMISSION

Contact the opening with contaminated object or penetration through injuries.

PATHOGENICITY-

Pseudomonas aeruginosa causes:-

1.      Skin infections especially at burn sites wounds pressure sores and ulcers, often as a secondary invader.

2.      Urinary infection, usually following catheterization or associated with chronic urinary infections.

3.      Respiratory infections especially in-patients with cystic fibrosis or conditions that cause immunosuppression.

4.      External ear infections (otitis external).

5.      Eye infections usually (hospital – acquired).

6.      Septicaemia especially in persons already in poor health

Pseudomonas pseudomallei

·         Prendomonas prseundomallei; causes melioidosis (pneumoenteritis) in humans and animals the bacteria enter open wounds but can also be inhaled.

·         In melioidosis, pus filled nodules and abscesses form in these lungs, spleen, lever, joints, skin or subcutaneous tissues

·         Severe diarrhoea and vomiting may occur and occasionally septicaemia. Fever and a rash are usually present laboratory diagnosis.

·         Specimens; Depending on the site of infection, specimens include pus, urine, sputum and effusions for microscopy and culture, and occasionally blood for culture.

·         Specimens; that may contain prseudomonas pseudomallei must be marked HIGH RISK and; handled with great care. This specie is highly infections

Describe the laboratory diagnosis Salmonella 

1.SPECIMENS

Depending on the site of infection, these include urine, pus and sputum

2.CULTURE CHARACTERISTICS

·         Pseudomonas aeruginosa is an obligatory aerobe and is usually recognized by the blue – green pyocyanin pigment it produces.

·         Usually produces large, flat; haemolytic colonies on blood agar

·         Also it grows well on nutrient agar, Macconkey agar and other media containing bile salts and also on centrimide agar.

·         When grown on Kligler iron agar, it produces a characteristic pink – red slope and butt.

·         Pseudomonas pseudomallei produces non – haemolytic, small ringed, and striated colonies on blood agar after overnight aerobic incubation. On Macconkey agar colonies have a rough annd corrugated appearance. Cultures give off an ammoniacal smell. A pellicle (skin) is formed on broth cultures.

·         Preudomonas species grow well at room temperature Pseudomonas aeniginosa is also able to grow at 41 – 42 ^oc

Clinical features.

·         Severe diarrhoea and vomiting

·         Otitis external

·         Infected wounds and ulcers on the skin

·         Fever and rash.

3.BIOCHEMICAL TESTS

·         .All strains are strongly oxidase positive

·         Pseudomonas species are catalase positive

·         Pseudomonas species are indole negative

·         mostly are citrate positive

·         Preudomonads produce acid from carbohydrate media by oxidation not by fermentation. Glucose is oxidised and also maltose by most species except Proteus aeruginosa

PREVENTION AND CONTROL:

• Eliminating the source of infection, particularly by control of carriers.
• Treating the infected cases

·         Avoid contaminating the open areas with contaminated microbial

·         Sanitation in the hospital to avoid nasocomial infections