• The four main species:
a. P .Vulgaris
b. P .Mirabilis
c. P .Myxofacien
d. P. Penneri
Habitat:
• soil, water and intestine of man .
Morphology:
• Gram negative bacillj, very pleomorphic and
highly motile .
Cultural characteristics:
They can grow on ordinary media with fishy bad odour.
Exhibit the characteristic feature of swarming motility
Biochemical activities:
Urease positive (
pink-red pH>8.1)
Urea + Water
urease
ammonia+ carbon dioxide
Phenolphthalein
(colorless)
ammonia phenolphthalein
(
pink-red
).
Phenylalanine deaminase test positive.
L-phenylalanine
phenylalanine deaminase
phenylpyruvic acid+
ammonia
.
Phenylpyruvic acid + Fecl3 (10%)
acid
green color
IMViC test: V+-V. , TSI (K/A) +H2S
Urease test
Phenylalanine
deaminas
Non fermenter gram negativebacilli
Pseudomonas
• NF gram negative bacilli:
1. Positive cytochrom oxidase
2. Lack of evidence of glucose
fermentation
3. Failure to grow on MacConkey
agar
Pseudomonas General
characters
Pseudomonas spp. are aerobic, non-spore-forming, gram
negative rods which are straight or slightly curved. They are
oxidase positive and are motile by one or more polar
flagella.
Habitat:
Water, soil, plants and GIT of man.
Morphology:
Straight and slender gram negative bacilli. Range 1-5µm in
length and 0.5-1µm in width.
• Aerobic, the colonies are 2-4mm in diameter, convex and they give
and can
sweetish aromatic, or grape-like odour. Can grow at 42 C
produce the
following pigments:
1. Pyocyanin:
Blue
.
2.
Pyoverdin:
Green or yellowish green
.
3. Pyorubin:
Red
.
4.
Pyomelanin:
Black or dark brown
.
• Biochemical reactions:
1. Oxidase positive.
2. Catalase positive.
3. Citrate utilization test is positive.
4. No n lactose fermenter.
5.
Oxidative
utilization or degradation of glucose.
7. Oxidative fermentative test (O.F. medium).
This is a sensitive test for the detection for the bacteria
that utilize
glucose oxidatively
.
open tube
acid (
yellow
)
acid (
yellow
)
alkaline (
green
)
covered tube
alkaline (
green
)
acid (
yellow
)
metabolism
oxidative
fermentative
alkaline (
green
)nonsaccharolytic
Motility test
Principle
The end products of fermentation are relatively strong acid that can be
detected in a conventional fermentation test medium. The acid formed
in oxidative degradation of glucose is extremely weak so it is tested by
semisolid OF medium. The concentration of peptone is deceased 1%to
0.2% the concentration of CHO is increased from 0.5-
1%.
(pepton:
CHO
1:5( The
lower protein/ CHO ratio reduce the formation of alkine amines
that can neutralize the small quantities of weak acid may form from
oxidative metabolism. The large amount of CHO serve to increase
the
amount of acid that can potentially be formed. The semisolid
consistency of the agar permits acids that formed on the surface.
