Pseudomonas

Lab Eighteen:- ________________ Medical Microbiology
Prepared by: Luma J. Witwit


Pseudomonas

Pseudomonas are motile, Gram-negative rods that utilize glucose oxidatively (oxidase +) . These bacteria are clinically important because they are resistant to most antibiotics and they are capable of surviving in conditions that few other organisms can tolerate . it is a major cause of hospital acquired (nosocomial) infections.

Disease:-
Cystic fibrosis, UTI (indwelling catheters ) , sepsis, pneumonia, pharyngitis.

P. aeruginosa:-
Pseudomonas aeroginosa is the most frequently isolated non-fermenter, it has several features that distinguish it from other species of pseudomonas.
- It can grow at 42 degree.
- Produces a bluish pigment ( pyocyanin , pyoviridin ) and a greenish pigment.
- Characteristic fruity odor growth.
- Obligate aerobe.

Specimens:-
Skin lesions, pus, urin, blood, spinal fluid and sputum.

Laboratory diagnosis
1- Gram stain ( G- bacilli )
2- Blood agar ( ? hemolysis )
3- MacConKey agar (NLF)
4- King A medium (selective for P. auroginosa) to produce pyocyanin pigment.
6- king B medium (selective for P.fluorescense) to produce fluorecen pigment.
7- Oxidase: positive.
8- TSI.
9- Motility.
10- O.F. media (Oxidation and fermentation media).
11- IMVC tests.


Oxidase test:-
Oxidase test reagent: Prepares immediately by solved (1 gm) of (Tetra-methyl P.phenylene diamine dihydrochloride ) in 100 ml of D.W.
The solution kept in black bottle in dark place.

Method:-
transfer few colonies by wooden stick to filter paper saturated by oxidase reagent.
The purple color appearance indication the positive test.