Transcript Pseudomonas
PSEUDOMONAS
Introduction
Large group of aerobic
non sporing
gram negative
motile by polar flagella
ubiquitous
oppurtunistic infections
newer genera-Burkholderia
Stenotrophomonas
Species
Pseuomonas aeruginosa
Stenotrophomonas maltophila
Burkholderia cepacia
Burkholderia mallei
Burkholderia pseudomallei
Pseudomonas aeruginosa
Morphology
slender,Gram negative bacillus
size-1.5 microns-3*1.5microns
motile by polar flagella
non capsulated though some mucoid
strains may sometimes occur
some are pilated
Cultural characteristics
Obligate aerobe
Wide range of temperature 5°c-42°c
optimum 37°c
Ordinary media –
large,opaque,irregular,with distinctive
musty,mawkish,earthy smell
Cont..
Nutrient agar Colonies are smooth,large,translucent,low
convex,2-4mm in diameter.
Produce sweetish aromatic odour
Greenish blue pigment diffuses
Cont..
Blood agar
Similar to nutrient agar
Many are haemolytic
Mac conkey agar
Colourless,non lactose fermenters
Cetrimide agar
selective media
Pigment production
Pyocyanin
Bluish green phenazine pigment
Soluble in chloroform and water
Not produced by other species
Pyoverdin(fluorescin)
It is a greenish yellow pigment
Insoluble in chloroform but soluble in water
Produced by many other species
Pyocyanin
Pyoverdin
Cont..
Pyorubin
Reddish brown pigment
Insoluble in chloroform but soluble in water
pyomelanin
Brown to black pigment
Production is uncommon
Biochemical reactions
O/F test-oxidative
Catalase-positive
Oxidase-positive
Nitrate reduction-positive
Cont..
Indole test-negative
Methyl red test-negative
Vp test-negative
Citrate test-positive
Urease test-negative
Cont…
Sugar fermentation tests
Glucose-only acid
Lactose-negative
Sucrose-negative
Mannitol-negative
Resistance
Susceptible to
heat,killed at 55°c in one hour
acids
beta glutarldehyde
Silver salts
strong phenolic disinfectants
So,silver sulphonamide as a topical cream in
burns is used
Cont…
Resistant to
chemical agents
common antiseptics
disinfectants -ammonium compounds
chlroxylenol
hexachlorophane
antibiotics -aminoglycosides
cephalosporins
pencillins
Antigenic structure
O antigens
Possesses 19 distinct,group specific O antigens
Heat labile
H antigens
Two heat labile antigens recognised in
Ps.aeruginosa
Toxins and enzymes
Extracellular products
Pyocyanin inhibits mitochondrial enzymes and causes
disruption and cessation of ciliary beat on ciliated nasal
epthelium
Extracellular enzymes and haemolysins
Produces proteases,haemolysins and lipases
Exotoxins
Produces two exotoxns A and S
Endotoxins
It is a lipopolysaccharide have pyrogenic action
Typing methods
Bacteriocin typing
Three types of bacteriocins are produced-R,F,S
Pyocin produced by test strain is employed to
assess the growth inhibition of 13
Depending upon the growth inhibition of 13
indicators strains,105 types are recognised
Most popular method used
Cont..
Phage typing
Serotyping
based on O and H,17 serotypes of
Ps.aeruginosa are recognised
Molecular Method
Restriction endonuclease typing with
pulsed-field gel electrophoresis(PAGE) is most
reliable
PATHOGENESIS
Important agent in causing nosocomial
infections
Most common infections are
Urinary tract infections following catheterisation
Acute purulent meningitis following lumbar
puncture
Post-tracheostomy pulmonary infection
Septicaemia in debilitated patients
cont..
Wound and burn infections
Chronic otitis media and otitis externa
Eye infections
Acute necrotising vasculitis
Infantile diarrhoea
Mechanism Of Pathogenesis
Caused by
exotoxins,proteases,elastases,haemolysins,lip
ases and enterotoxins
Exotoxin A-lethal toxin
Elastases-haemorrhagic lesions
Enterotoxins-diarrhoeal disease
Slime layer acts as a capsule and enhances
virulence
Thank you
HAEMOPHILUS
INTRODUCTION
HAEMOPHILUS
INFLUENZAE
MORPHOLOGY
SMALL [ 1.0 X 0.3 MICRONS]
GRAM NEGATIVE
NON MOTILE
NON SPORING
EXHIBIT PLEOMORPHISM
CULTURAL
CHARACTERISTICS
FACTOR X
FACTOR V
HEAT STABLE
HEAT LABILE
HEMIN
BACTERIAL
VITAMIN
AEROBIC
RESPIRATION
ANEROBIC
RESPIRATION
CONT…
AEROBIC
GROWS ANEROBICALLY ALSO
OPTIMUM TEMPERATURE-37C
SOME STRAINS REQUIRE 10% CO2
BLOOD AGAR-SCANTY GROWTH
SATELLITISM
Staph.aureus is streaked across a plate of
blood agar on which a specimen containing
H.influenzae has inoculated
After overnight incubation Colonies
large -along the streak of Staph.aureus
small –farther away
satellitism
CONT…
LEVINTHAL`S MEDIUM
Boiling and filtering a mixture of blood and
nutrient broth
Capsulated strains produce translucent colonies
FILDES AGAR
By adding a peptic digest of blood to nutrient
agar
Best for primary isolation
Copious growth
BIOCHEMICAL REACTIONS
Catalase-positive
Oxidase-positive
Glucose,Xylose-fermented with acid
production
Lactose,Sucrose,Mannitol-not fermented
RESISTANCE
Destroyed by heating
refrigeration
drying
disinfectants
Cultures may be preserved for about a
month on choclate agar slopes in screw
capped bottles
Long term preservation –culture may be
lyophilised
ANTIGENIC PROPERTIES
3 Major surface antigens
Capsular polysaccharide
Outer membrane protien
Lipo oligosaccharide
Major antigenic determinant of capsulated strains
Capsular polysaccharide
Pittman classified into 6 capsular strains i.e type
a to f
•Meningitis belong to type b strain
•Type b strain contains pentose sugars
ribose &ribitol instead of hexoses &
hexosamines in other 5 serotypes
•Capsular polyribosyl ribitol
phosphate antigen of Hib induces
IgG IgM IgA antibodies which are
bactericidal and protective
CONT….
Strains lacking a capsule cannot be typed
and are called NON TYPABLE
STRAINS
Outer membrane protein antigens of H
influenzae type b have been classified into
13 sub types
Lipo oligosaccharides are antigenically
complex
PATHOGENECITY
Exclusively human pathogen
Not pathogenic for animals but intra
peritoneal inoculation of large doses is fatal
in mice,guinea pigs &rabbits
Diseases due to H influnzae considered
under 2 groups –invasive and non invasive
INVASIVE
•Spread through
Blood
NON INVASIVE
•Spread through local
invasion
•Meningitis,arthritis, •Otitis media,sinusitis
endocardits,conjuctivit
is,pancarditis
•Seen in children
•Seen in adults
•Caused by capsulated •Caused by non
strains
capsulated strains
CLINICAL MANIFESTATIONS
MENINGITIS
Bacilli reach meninges from nasopharynx
through blood stream
Common in children
LARYNGO EPIGLOTTIS
Acute inflammaton of epiglottis with obstructive
laryngitis
Children above 2 years
CONT….
PNEUMONIA
Infants accompanied by empyema
Older children & adults by lobar pneumonia
These are primary infections due to
capsulated strains
Broncho pneumonia may occur as
secondary infection due to non capsulated
strains
CONT…
SUPPURATIVE LESIONS
Arthritis,endocarditis& pericarditis may result
from hematogenous dissemination
Otitis media occurs by direct spread from
nasopharynx
BRONCHITIS
Associated with pneumococci in acute
exacerbationof chronic bronchitis
&bronchiectasis
LAB DIAGNOSIS
1.SPECIMENS
CSF
Blood
Throat swab
Sputum
Pus
Aspirates from joints ,middle ears
2.COLLECTION &TRANSPORT
Collected in sterile containers & under
aseptic conditions
Very sensitive to low temp so should not
be refrigerated
Transported to laboratory with out delay
Inoculated on culture media immediately
CONT.....
3.DIRECT MICROSCOPY
Gram staining
Immunoflouroscence and quellung
reaction
Antigen detection
Latex
agglutination
Co-agglutination
Counter immuno electrophoresis
CONT…
4.CULTURE
CSF
culture
Blood culture
Sputum culture
5.COLONY MORPHOLOGY AND
STAINING
6.SEROTYPING
TREATMENT
Cefotaxime & Ceftazidime is the drug of
choice for meningitis
Ampicillin &Cotrimoxazole –respiratory
infections
Amoxycillin - clavulanate or clarithromycin
is more effective
EPIDEMIOLOGY &
PREVENTION
Infection transmitted by respiratory route
Immunity is type specific
Active immunization with Hib PRP vaccine
is indicated
Conjugate Hib PRP is used for younger
children
Rifampicin -4 days prevents secondary
infection in contacts & also eradicates
carrier state
Haemophilus aegyptius
KOCH –WEEKS BACILLUS
Non capsulated
Causes highly contagious form of
conjuctivitis [ pink eye ]
Causative agent of Brazilian purpuric fever
[BPF]
Responds to local sulphanamides &
gentamicin
Haemophilus ducreyi
Ducrey demonstrated in chancroid lesions
Short ,ovoid bacillus
Gram nagative often may appear gram positive
& frequently show bipolar staining
May be arranged in small groups or whorls or in
parallel chains giving a SCHOOL OF FISH or
RAIL ROAD TRACK appearance
CONT…
Can be grown on fresh clotted rabbit blood
May also grown on chorio allontioc membrane
of chick embryo
On choclate agar enriched with isovitalex and
fetal calf serum & containing vancomycin as a
selective agent
Forms small ,grey ,translucent colonies after
incubation at 35 c under 10 % co2 & high
humidity in 2 – 8 days
CONT…
Antigenically homogenous
Cultures may be identified by agglutinatoin
with anti serum
Susceptible to sulphonamides & many
antibiotics
Erythromycin ,Cotrimoxazole
,Ciprofloxacin may be used for treatment
Choclate agar
Haemophilus parainfluenzae
Requires factor V & not the factor X
Commensel in the upper respiratory tract
Causes bacterial endocarditis ,urethritis
,acute pharyngitis
Haemophilus haemolyticus
Requires both factor X & V
Commensal of upper respiratory tract
Strains that donot require factor X have
been designated as H parahaemolyticus
Haemophilus aphrophilus
Requires factor X but not factor V
Cause bacterial endocarditis ,brain abscess
,sinuisitis pneumonia
Strains requiring factor V but not factor X
have been termed as H paraaphrophilus
HACEK group bacteria
Fastidious slow growing bacteria
H-
Haemophilus species
ACE-
Cardiobacterium hominis
K -
Kingella kingae
Actinobacillus
Eikenella corrodens