Pseudomonas Basics
-
Upload
tummalapalli-venkateswara-rao -
Category
Documents
-
view
222 -
download
0
Transcript of Pseudomonas Basics
-
7/31/2019 Pseudomonas Basics
1/32
DR.T.V.RAO MD 1
Dr.T.V.Rao MDPSEUDOMONAS
-
7/31/2019 Pseudomonas Basics
2/32
PSEUDOMONAS
DR.T.V.RAO MD 2
A large group of aerobic, non sporing gram
negative bacteria motile by polar flagella
Found I nature water, soil, other moistenvironments
Some of them are pathogenic to plants
Creation of new genera such as
Burkholderia. Stenotrophomnonas
-
7/31/2019 Pseudomonas Basics
3/32
- Widely distributed in
soil and water
- Gram negative rods
- Aerobic
- Motile
- Produce water-solublepigments
Opportunistic
pathogens
GENERAL CHARACTERISTICS
DR.T.V.RAO MD 3
-
7/31/2019 Pseudomonas Basics
4/32
MORPHOLOGY
DR.T.V.RAO MD 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.
-
7/31/2019 Pseudomonas Basics
5/32
P. aeruginosa
Forms round colonies with afluorescent greenish color, sweet
odor, and b-hemolysis.
Pyocyanin- nonfluorescentbluish pigment;
pyoverdin- fluorescentgreenish pigment;
pyorubin, andpyomelanin
Some strains have a prominentcapsule (alginate).
Identification of P. aeruginosais usually based on oxidase test
and its colonial morphology: b-hemolysis, the presence of
characteristic pigments and sweet odor, and growth at 42 oC.
-
7/31/2019 Pseudomonas Basics
6/32
CULTURAL CHARACTERS
DR.T.V.RAO MD 6
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.
-
7/31/2019 Pseudomonas Basics
7/32
Motile (by single or multiple polar flagella)
gram-negative rodsObligate (strict) aerobes (most strains)Oxidase (usually) and catalase positive
Nonfermentative chemoheterotrophicrespiratory metabolismMinimal nutritional reqts.; Many organic
compounds used as C and N sources, but
only a few carbohydrates by oxidativemetabolism Glucose used oxidatively
Lactose negativeon MacConkeys agar
Characteristics of Pseudomonas aeruginosa
DR.T.V.RAO MD 7
-
7/31/2019 Pseudomonas Basics
8/32
PIGMENT PRODUCTION
DR.T.V.RAO MD 8
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
-
7/31/2019 Pseudomonas Basics
9/32
BIOCHEMICAL REACTIONS
DR.T.V.RAO MD 9
Oxidative and Non fermentative
Glucose is utilized oxidatively
Indole, MR and VP and H2 S tests are
negative
Catalase, Oxidase, and Arginine testsare positive
-
7/31/2019 Pseudomonas Basics
10/32
TYPING AND IMPORTANCE
DR.T.V.RAO MD 10
Important cause of Hospital Infections
Important for epidemiological purpose
Serotyping Bacteriocins typing
Pyocyanin
Aeruginosin typing
Restriction endonuclease typing with pulsed gel
electrophoresis
-
7/31/2019 Pseudomonas Basics
11/32
RESISTANCE
DR.T.V.RAO MD 11
Killed at 55oc in on 1 hour
High resistance to chemical agents
Resistance to quaternary ammoniumcompounds.Chlorxylenol
Resistant to Hexchlorophenes
Grows also in antiseptic bottles Dettol as cetrimide as selective medium
Sensitive to acids silver salts, beta glutaraldehyde
-
7/31/2019 Pseudomonas Basics
12/32
WHAT ANTIBIOTICS TO USE
DR.T.V.RAO MD 12
Aminoglycosides
Gentamycin, Amikacin, Cephalosporins
Cefotaxime. Ceftazidime. Ofloxacin,
Piperacillin, ticarcillin
Local application, colistin, polymyxin
-
7/31/2019 Pseudomonas Basics
13/32
PATHOGENICITY
DR.T.V.RAO MD 13
Blue pus
Causing the nosocomial infection
Suppurative otitis Localised and generalised infections
Urinary tract infection after catheterization
Iatrogenic meningitis
Post tracheostomy pulmonary infections
-
7/31/2019 Pseudomonas Basics
14/32
P. aeruginosaPathogenesis 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 normaldefenses, e.g.,
1. Disruption of mucous membrane and skin.
2. Usage of intravenous or urinary catheters.
3. Neutropenia (as in cancer therapy).
-
7/31/2019 Pseudomonas Basics
15/32
P. aeruginosa
Antigenic structure,enzymes, and toxins
Pili and nonpilus adhesins.
Capsule (alginate, glycocalyx):
seen in cultures from patientswith cystic fibrosis.
LPS- endotoxin, multiple
immunotypes.
Pyocyanin: catalyzes
production of toxic forms ofoxygen that cause tissue
damage. It also induces IL-8
production. Pyoverdin: a
siderophore.
ProteasesSerine protease,
metalloprotease andalkaline
proteasecause tissue
damage and help bacteriaspread.
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
-
7/31/2019 Pseudomonas Basics
16/32
PATHOGENESIS AND IMMUNITY
DR.T.V.RAO MD 16
P. aeruginosacan infect almost anyexternal site or organ.
P. aeruginosais invasive and toxigenic. It
attaches to and colonizes the mucous membraneor skin, invade locally, and produces systemicdiseases and septicemia.
P. aeruginosais resistant to many antibiotics. It
becomes dominant when more susceptiblebacteria of the normal flora are suppressed.
-
7/31/2019 Pseudomonas Basics
17/32
Septicaemia
Endocarditis
Ecthyma gangrenous
Infantile diarrhoea
Shanghai fever
Disabling eye infections
Survive with minimalnutrients
CLINICAL PRESENTATIONS
DR.T.V.RAO MD 17
-
7/31/2019 Pseudomonas Basics
18/32
WHO IS MORE SUSCEPTIBLE TO
INFECTION
DR.T.V.RAO MD 18
This bacterium is of particular concern to
individuals with cystic fibrosis who are highly
susceptible to pseudomonas lung infections.
Pseudomonas aeruginosa is also of graveconcern to cancer and burn patients as well as
those people who are immunocompromised. The
case fatality rate for individuals infected withPseudomonas aeruginosa approaches 50
percent.
-
7/31/2019 Pseudomonas Basics
19/32
Pseudomonas aeruginosa
is the most frequently
encountered lung pathogen
in patients with cystic
fibrosis (CF). Followinginitial, often intermittent,
episodes of infection, it
becomes a permanently
established component ofthe chronically infected
lung in more than 80% of
patients and confers an
adverse prognosis
PSEUDOMONAS AND CYSTIC FIBROSIS
DR.T.V.RAO MD 19
-
7/31/2019 Pseudomonas Basics
20/32
Respirators
Endotracheal
tubes Can be Infected
All equipment'sto be sterilized
INFECTION OF EQUIPMENT'S
DR.T.V.RAO MD 20
-
7/31/2019 Pseudomonas Basics
21/32
PSEUDOMONAS AND URINARY TRACT
INFECTIONS
DR.T.V.RAO MD 21
Pseudomonal UTIs are usually hospital-acquired
and are associated with catheterization,
instrumentation, and surgery. These infections
can involve the urinary tract through anascending infection or through bacteriuic spread.
In addition, these infections are a frequent
source of bacteraemia. No specificcharacteristics distinguish this type of infection
from other forms of UTI.
-
7/31/2019 Pseudomonas Basics
22/32
Toxic extracellular products
in culture filtrates
Exotoxin A and S
Exotoxin A acts as NADaseresembling Diphtheria toxin
Proteases,elastatese
hemolysins and enterotoxin
Slime layer and Biofilms
TOXINS AND ENZYMES IN
PSEUDOMONAS
DR.T.V.RAO MD 22
-
7/31/2019 Pseudomonas Basics
23/32
PSEUDOMONAS AERUGINOSA AN
IMPORTANT OPPORTUNISTIC PATHOGEN
DR.T.V.RAO MD 23
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 anopportunistic pathogen of humans. The
bacterium almost never infects uncompromised
tissues, yet there is hardly any tissue that itcannot infect if the tissue defences are
compromised in some manner
-
7/31/2019 Pseudomonas Basics
24/32
P.AEROGINOSA IS AN OPPORTUNISTIC
PATHOGEN
DR.T.V.RAO MD 24
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, mucousmembrane) is lost or an underlying immune
deficiency (eg, neutropenia,
immunosuppression) is present. Adding to itspathogenicity, this bacterium has minimal
nutritional requirements and can tolerate a wide
variety of physical conditions
-
7/31/2019 Pseudomonas Basics
25/32
PSEUDOMONAS PROMINENT HOSPITAL
ACQUIRED INFECTIONS
DR.T.V.RAO MD 25
It causes urinary tract infections,
respiratory system infections, dermatitis,
soft tissue infections, bacteraemia, boneand joint infections, gastrointestinal
infections and a variety of systemic
infections, particularly in patients withsevere burns and in cancer and AIDS
patients who are immunosuppressed.
-
7/31/2019 Pseudomonas Basics
26/32
DIAGNOSIS OF P.AEROGINOSA
INFECTION
DR.T.V.RAO MD 26
Diagnosis ofP,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 blueagar. 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 42C. Fluorescence under ultraviolet light is helpfulin early identification ofP.s aeruginosa colonies.
Fluorescence is also used to suggest the presence of
P. aeruginosa in wounds.
-
7/31/2019 Pseudomonas Basics
27/32
Pseudomonas sp. develop as easilydistinguishable blue-green coloured
colonies, clearly visible under normal
lighting conditions. Other bacterial
species are inhibited or give
colourless colonies. Pseudomonasaeruginosa, Pseudomonas
fluorescens, Pseudomonas putida
and Pseudomonas fragilis all give
typical blue-green colony colouration
and can be studied directly byserotyping or biochemical methods.
IDENTIFICATION WITH CHROMAGAR
DR.T.V.RAO MD 27
-
7/31/2019 Pseudomonas Basics
28/32
LABORATORY IDENTIFICATION OF
DIAGNOSIS OF P.AEROGINOSA INFECTIONS
DR.T.V.RAO MD 28
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 blueagar. 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 helpfulin early identification of P. aeruginosa colonies and may
also help identify its presence in wounds.
-
7/31/2019 Pseudomonas Basics
29/32
TREATING PSEUDOMONAS INFECTIONS
DR.T.V.RAO MD 29
Combined antibiotic therapy is generally
required to avoid resistance that develops
rapidly when single drugs are employed.Avoid using inappropriate broad-spectrum
antibiotics, which can suppress the normal
flora and permit overgrowth of resistantpseudomonads.
-
7/31/2019 Pseudomonas Basics
30/32
PSEUDOMONAS AERUGINOSA A RESISTANT
PATHOGEN
DR.T.V.RAO MD 30
Pseudomonas aeruginosa is frequently resistant
to many commonly used antibiotics. Although
many strains are susceptible to gentamicin,
tobramycin, colistin, and amikacin, resistantforms have developed. The combination of
gentamicin and carbenicillin is frequently used
to treat severe Pseudomonas infections. Severaltypes of vaccines are being tested, but none is
currently available for general use.
-
7/31/2019 Pseudomonas Basics
31/32
P. aeruginosa
Prevention and Control
Pseudomonasspp. 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 andcross-contamination of patients by medical personnel.
High risk population: patients receiving broad-spectrum
antibiotics, with leukemia, burns, cystic fibrosis, andimmunosuppression.
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.
-
7/31/2019 Pseudomonas Basics
32/32
DR.T.V.RAO MD 32
Programme created by Dr.T.V.Rao MD
for Medical and Paramedical Students
Email