Adnan Ahmad [Pseudomonas]

1. 1
PSEUDOMONAS

2. PSEUDOMONAS
2
• A large group of aerobic, non sporing gram
negative bacteria motile by polar flagella
• Found I nature water, soil, other moist
environments
• Some of them are pathogenic to plants
• Creation of new genera such as
Burkholderia. Stenotrophomnonas

3. - Widely distributed in
soil and water
- Gram negative rods
- Aerobic
- Motile
- Produce water-soluble
pigments
• Opportunistic
pathogens
GENERAL CHARACTERISTICS
3

4. MORPHOLOGY
4
• They are slender gram negative bacillus, 1.5 – 3 microbes x 0.5
microns
• Monoflgellar ?
• Non capsulated but many strains have mucoid slime layer
• Isolates from Cystic fibrosis patients have abundance of
extracellular polysaccharides composed of alginate polymers
• Escape the defence mechanisms by loose capsule in which
micro colonies of bacillus are enmeshed and protected from
host defences.

5. P. aeruginosa
Forms round colonies with a
fluorescent greenish color, sweet
odor, and -hemolysis.
Pyocyanin- nonfluorescent
bluish pigment;
pyoverdin- fluorescent
greenish pigment;
pyorubin, and pyomelanin
Some strains have a prominent
capsule (alginate).
Identification of P. aeruginosa is usually based on oxidase test
and its colonial morphology: b-hemolysis, the presence of
characteristic pigments and sweet odor, and growth at 42 C.o

6. CULTURAL CHARACTERS
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• Obligate aerobe, but grow anaerobically if nitrate is
available
• Growth occurs at wide range of temperatures 6-42 c
the optimum being 37 c
• Growth on ordinary media producing large opaque
irregular colonies with distinctive musty mawkish or
earthy smell.
• Iridescent patches with metallic sheen are seen in
cultures on nutrient agar.
• In broth forms dense turbidity with surface pellicle.

7. Motile (by single or multiple polar flagella)
gram-negative rods
Obligate (strict) aerobes (most strains)
Oxidase (usually) and catalase positive
Nonfermentative chemoheterotrophic
respiratory metabolism
Minimal nutritional reqts.; Many organic
compounds used as C and N sources, but
only a few carbohydrates by oxidative
metabolism
• Glucose used oxidatively
• Lactose negative on MacConkey’s agar
Characteristics of Pseudomonas aeruginosa
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8. PIGMENT PRODUCTION
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Some strains produce diffusible pigments:
• Pyocyanin (blue); fluorescein (yellow);
pyorubin (red)
P. aeruginosa produces characteristic
grape-like odor and blue-green pus &
colonies
Broad antibiotic resistance

9. BIOCHEMICAL REACTIONS
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• Oxidative and Non fermentative
• Glucose is utilized oxidatively
• Indole, MR and VP and H2 S tests are
negative
• Catalase, Oxidase, and Arginine tests
are positive

10. TYPING AND IMPORTANCE
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• Important cause of Hospital Infections
• Important for epidemiological purpose
• Serotyping
• Bacteriocins typing
• Pyocyanin
• Restriction endonuclease typing with pulsed gel
electrophoresis

11. RESISTANCE
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• Killed at 55oc in on 1 hour
• High resistance to chemical agents
• Resistance to quaternary ammonium
compounds.Chlorxylenol
• Resistant to Hexchlorophenes
• Grows also in antiseptic bottles
• Dettol as cetrimide as selective medium
• Sensitive to acids silver salts, beta glutaraldehyde

12. WHAT ANTIBIOTICS TO USE
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• Aminoglycosides
• Gentamycin, Amikacin, Cephalosporins
• Cefotaxime. Ceftazidime. Ofloxacin,
• Piperacillin, ticarcillin
• Local application, colistin, polymyxin

13. PATHOGENICITY
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• Blue pus
• Causing the nosocomial infection
• Suppurative otitis
• Localised and generalised infections
• Urinary tract infection after catheterization
• Iatrogenic meningitis

14. P. aeruginosa
Pathogenesis and Immunity
This organism is widely distributed in nature
and is commonly present in moist environments
in hospitals. It is pathogenic only when
introduced into areas devoid of normal
defenses, e.g.,
1. Disruption of mucous membrane and skin.
2. Usage of intravenous or urinary catheters.
3. Neutropenia (as in cancer therapy).

15. P. aeruginosa
Antigenic structure,
enzymes, and toxins
Pili and nonpilus adhesins.
Capsule (alginate, glycocalyx):
seen in cultures from patients
with cystic fibrosis.
LPS- endotoxin, multiple
immunotypes.
Pyocyanin: catalyzes
production of toxic forms of
oxygen that cause tissue
damage. It also induces IL-8
production. Pyoverdin: a
siderophore.
Proteases
Serine protease,
metalloprotease and alkaline
protease cause tissue
damage and help bacteria
spread
Phospholipase C: a hemolysin
Exotoxin A: causes tissue
necrosis and is lethal for animals
(disrupts protein synthesis);
immunosuppressive.
Exoenzyme S and T: cytotoxic to
host cells.
Pathogenesis

16. PATHOGENESIS AND IMMUNITY
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• P. aeruginosa can infect almost any
external site or organ.
• P. aeruginosa is invasive and toxigenic. It
attaches to and colonizes the mucous membrane
or skin, invade locally, and produces systemic
diseases and septicemia.
• P. aeruginosa is resistant to many antibiotics. It
becomes dominant when more susceptible
bacteria of the normal flora are suppressed.

17. • Septicaemia
• Endocarditis
• Ecthyma gangrenous
• Infantile diarrhoea
• Shanghai fever
• Disabling eye infections
• Survive with minimal
nutrients
CLINICAL PRESENTATIONS
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18. WHO IS MORE SUSCEPTIBLE TO
INFECTION
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• This bacterium is of particular concern to
individuals with cystic fibrosis who are highly
susceptible to pseudomonas lung infections.
Pseudomonas aeruginosa is also of grave
concern to cancer and burn patients as well as
those people who are immunocompromised. The
case fatality rate for individuals infected with
Pseudomonas aeruginosa approaches 50
percent.

19. • Pseudomonas aeruginosa
is the most frequently
encountered lung pathogen
in patients with cystic
fibrosis (CF). Following
initial, often intermittent,
episodes of infection, it
becomes a permanently
established component of
the chronically infected
lung in more than 80% of
patients and confers an
adverse prognosis
PSEUDOMONAS AND CYSTIC FIBROSIS
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20. • Toxic extracellular products
in culture filtrates
• Exotoxin A and S
• Exotoxin A acts as NADase
resembling Diphtheria toxin
• Proteases,elastatese
hemolysins and enterotoxin
• Slime layer and Biofilms
TOXINS AND ENZYMES IN
PSEUDOMONAS
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21. PSEUDOMONAS AERUGINOSA AN
IMPORTANT OPPORTUNISTIC PATHOGEN
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• Pseudomonas aeruginosa is an opportunistic
pathogen, meaning that it exploits some break in
the host defences to initiate an infection. In fact,
Pseudomonas aeruginosa is the epitome of an
opportunistic pathogen of humans. The
bacterium almost never infects uncompromised
tissues, yet there is hardly any tissue that it
cannot infect if the tissue defences are
compromised in some manner

22. P.AEROGINOSA IS AN OPPORTUNISTIC
PATHOGEN
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• P,aeroginosa is an opportunistic pathogen. It
rarely causes disease in healthy persons. In
most cases of infection, the integrity of a
physical barrier to infection (eg, skin, mucous
membrane) is lost or an underlying immune
deficiency (eg, neutropenia,
immunosuppression) is present. Adding to its
pathogenicity, this bacterium has minimal
nutritional requirements and can tolerate a wide
variety of physical conditions

23. PSEUDOMONAS PROMINENT HOSPITAL
ACQUIRED INFECTIONS
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• It causes urinary tract infections,
respiratory system infections, dermatitis,
soft tissue infections, bacteraemia, bone
and joint infections, gastrointestinal
infections and a variety of systemic
infections, particularly in patients with
severe burns and in cancer and AIDS
patients who are immunosuppressed.

24. DIAGNOSIS OF P.AEROGINOSA
INFECTION
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• Diagnosis of P,aeroginosa infection depends upon
isolation and laboratory identification of the bacterium.
It grows well on most laboratory media and commonly
is isolated on blood agar or eosin-methylthionine blue
agar. It is identified on the basis of its Gram
morphology, inability to ferment lactose, a positive
oxidase reaction, its fruity odour, and its ability to grow
at 42°C. Fluorescence under ultraviolet light is helpful
in early identification of P.s aeruginosa colonies.
Fluorescence is also used to suggest the presence of
P. aeruginosa in wounds.

25. Pseudomonas sp. develop as easily
distinguishable blue-green coloured
colonies, clearly visible under normal
lighting conditions. Other bacterial
species are inhibited or give
colourless colonies. Pseudomonas
aeruginosa, Pseudomonas
fluorescens, Pseudomonas putida
and Pseudomonas fragilis all give
typical blue-green colony colouration
and can be studied directly by
serotyping or biochemical methods.
IDENTIFICATION WITH CHROMAGAR
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26. LABORATORY IDENTIFICATION OF
DIAGNOSIS OF P.AEROGINOSA INFECTIONS
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• Diagnosis of P. aeruginosa infection depends upon
isolation and laboratory identification of the bacterium.
It grows well on most laboratory media and commonly
is isolated on blood agar or eosin-methylthionine blue
agar. It is identified on the basis of its Gram
morphology, inability to ferment lactose, a positive
oxidase reaction, its fruity odour, and its ability to grow
at 42° C. Fluorescence under ultraviolet light is helpful
in early identification of P. aeruginosa colonies and may
also help identify its presence in wounds.

27. PSEUDOMONAS AERUGINOSA A RESISTANT
PATHOGEN
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• Pseudomonas aeruginosa is frequently resistant
to many commonly used antibiotics. Although
many strains are susceptible to gentamicin,
tobramycin, colistin, and amikacin, resistant
forms have developed. The combination of
gentamicin and carbenicillin is frequently used
to treat severe Pseudomonas infections. Several
types of vaccines are being tested, but none is
currently available for general use.

28. P. aeruginosa
Prevention and Control
Pseudomonas spp. normally inhabit soil, water, and vegetation
and can be isolated from the skin, throat, and stool of healthy
persons.
Spread is mainly via contaminated sterile equipment's and
cross-contamination of patients by medical personnel.
High risk population: patients receiving broad-spectrum
antibiotics, with leukemia, burns, cystic fibrosis, and
immunosuppression.
Methods for control of infection are similar to those for other
nosocomial pathogens. Special attention should be paid to sinks,
water baths, showers, hot tubs, and other wet areas.