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SEUDOMONAS
Introduction
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Large group of aerobicnon sporinggram negativemotile by polar flagella
ubiquitousoppurtunistic infectionsnewer genera-Burkholderia
Stenotrophomonas
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SpeciesPseuomonas aeruginosaStenotrophomonas maltophila
Burkholderia cepaciaBurkholderia malleiBurkholderia pseudomallei
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Pseudomonas aeruginosaMorphologyslender,Gram negative bacillus
size-1.5 microns-3*1.5micronsmotile by polar flagellanon capsulated though some mucoidstrains may sometimes occur some are pilated
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Cultural characteristicsObligate aerobeWide range of temperature 5c-42c
optimum 37c
Ordinary media large,opaque,irregular,with distinctivemusty,mawkish,earthy smell
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Cont..
Nutrient agar- Colonies are smooth,large,translucent,low convex,2-4mm in diameter.Produce sweetish aromatic odourGreenish blue pigment diffuses
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Cont..
Blood agar Similar to nutrient agar
Many are haemolyticMac conkey agar Colourless,non lactose fermenters
Cetrimide agar selective media
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Pigment productionPyocyanin Bluish green phenazine pigmentSoluble in chloroform and waterNot produced by other speciesPyoverdin(fluorescin) It is a greenish yellow pigmentInsoluble in chloroform but soluble in waterProduced by many other species
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Pyocyanin Pyoverdin
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Cont..
Pyorubin Reddish brown pigment
Insoluble in chloroform but soluble in water pyomelanin Brown to black pigment
Production is uncommon
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Biochemical reactionsO/F test-oxidativeCatalase-positive
Oxidase-positiveNitrate reduction-positive
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Cont..
Indole test-negativeMethyl red test-negative
Vp test-negativeCitrate test-positiveUrease test-negative
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ResistanceSusceptible to
heat,killed at 55c in one hour
acidsbeta glutarldehydeSilver salts
strong phenolic disinfectantsSo,silver sulphonamide as a topical cream inburns is used
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Cont
Resistant tochemical agents
common antisepticsdisinfectants -ammonium compounds
chlroxylenol
hexachlorophaneantibiotics -aminoglycosides
cephalosporins
pencillins
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Antigenic structureO antigensPossesses 19 distinct,group specific O antigens
Heat labileH antigens
Two heat labile antigens recognised in
Ps.aeruginosa
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Toxins and enzymesExtracellular products Pyocyanin inhibits mitochondrial enzymes and causesdisruption and cessation of ciliary beat on ciliated nasaleptheliumExtracellular enzymes and haemolysins Produces proteases,haemolysins and lipasesExotoxins Produces two exotoxns A and SEndotoxins It is a lipopolysaccharide have pyrogenic action
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Typing methodsBacteriocin typing
Three types of bacteriocins are produced-R,F,S
Pyocin produced by test strain is employed toassess the growth inhibition of 13Depending upon the growth inhibition of 13
indicators strains,105 types are recognisedMost popular method used
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Phage typing Serotyping
based on O and H,17 serotypes of Ps.aeruginosa are recognisedMolecular Method
Restriction endonuclease typing withpulsed-field gel electrophoresis(PAGE) is mostreliable
Cont..
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PATHOGENESISImportant agent in causing nosocomialinfectionsMost common infections areUrinary tract infections following catheterisation
Acute purulent meningitis following lumbar
puncturePost-tracheostomy pulmonary infectionSepticaemia in debilitated patients
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cont..
Wound and burn infectionsChronic otitis media and otitis externa
Eye infections Acute necrotising vasculitisInfantile diarrhoea
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Mechanism Of Pathogenesis
Caused by exotoxins,proteases,elastases,haemolysins,lip
ases and enterotoxinsExotoxin A-lethal toxinElastases-haemorrhagic lesionsEnterotoxins-diarrhoeal diseaseSlime layer acts as a capsule and enhances
virulence
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Thank you
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HAEMOPHILUS
INTRODUCTION
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HAEMOPHILUSINFLUENZAE
MORPHOLOGY SMALL [ 1.0 X 0.3 MICRONS]
GRAM NEGATIVENON MOTILENON SPORING
EXHIBIT PLEOMORPHISM
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CULTURALCHARACTERISTICS
FACTOR XHEAT STABLE
HEMIN
AEROBICRESPIRATION
FACTOR VHEAT LABILE
BACTERIAL VITAMIN
ANEROBICRESPIRATION
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CONT
AEROBICGROWS ANEROBICALLY ALSO
OPTIMUM TEMPERATURE-37CSOME STRAINS REQUIRE 10% CO2BLOOD AGAR-SCANTY GROWTH
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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.aureussmall farther away
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satellitism
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CONT LEVINTHAL`S MEDIUMBoiling and filtering a mixture of blood andnutrient brothCapsulated strains produce translucent coloniesFILDES AGAR By adding a peptic digest of blood to nutrientagarBest for primary isolationCopious growth
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BIOCHEMICAL REACTIONS
Catalase-positive
Oxidase-positive
Glucose,Xylose-fermented with acid
production
Lactose,Sucrose,Mannitol-not fermented
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RESISTANCE
Destroyed by heatingrefrigerationdrying
disinfectantsCultures may be preserved for about amonth on choclate agar slopes in screw
capped bottlesLong term preservation culture may belyophilised
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ANTIGENIC PROPERTIES
3 Major surface antigensCapsular polysaccharide
Outer membrane protienLipo oligosaccharideMajor antigenic determinant of capsulated strains
Capsular polysaccharidePittman classified into 6 capsular strains i.e type
a to f
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Meningitis belong to type b strain Type b strain contains pentose sugarsribose &ribitol instead of hexoses &hexosamines in other 5 serotypes
Capsular polyribosyl ribitolphosphate antigen of Hib induces
IgG IgM IgA antibodies which arebactericidal and protective
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PATHOGENECITY
Exclusively human pathogenNot pathogenic for animals but intra
peritoneal inoculation of large doses is fatalin mice,guinea pigs &rabbitsDiseases due to H influnzae considered
under 2 groups invasive and non invasive
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INVASIVE Spread through
Blood
Meningitis,arthritis,
endocardits,conjuctivitis,pancarditis
Seen in children
Caused by capsulatedstrains
NON INVASIVE Spread through local
invasion
Otitis media,sinusitis
Seen in adults
Caused by noncapsulated strains
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CLINICAL MANIFESTATIONSMENINGITIS
Bacilli reach meninges from nasopharynxthrough blood stream
Common in children
LARYNGO EPIGLOTTIS
Acute inflammaton of epiglottis with obstructivelaryngitisChildren above 2 years
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CONT.
PNEUMONIA Infants accompanied by empyema
Older children & adults by lobar pneumonia These are primary infections due tocapsulated strains
Broncho pneumonia may occur assecondary infection due to non capsulatedstrains
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CONT
SUPPURATIVE LESIONS Arthritis,endocarditis& pericarditis may resultfrom hematogenous dissemination
Otitis media occurs by direct spread fromnasopharynx
BRONCHITIS
Associated with pneumococci in acuteexacerbationof chronic bronchitis&bronchiectasis
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LAB DIAGNOSIS
1.SPECIMENSCSF
Blood Throat swabSputumPus
Aspirates from joints ,middle ears
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2.COLLECTION &TRANSPORT
Collected in sterile containers & underaseptic conditions
Very sensitive to low temp so should notbe refrigerated Transported to laboratory with out delay
Inoculated on culture media immediately
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CONT.....
3.DIRECT MICROSCOPY Gram staining Immunoflouroscence and quellung reaction
Antigen detection
Latex agglutinationCo-agglutinationCounter immuno electrophoresis
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TREATMENT
Cefotaxime & Ceftazidime is the drug of choice for meningitis
Ampicillin &Cotrimoxazole
respiratory infections Amoxycillin - clavulanate or clarithromycin
is more effective
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Haemophilus aegyptius
KOCH WEEKS BACILLUSNon capsulated
Causes highly contagious form of conjuctivitis [ pink eye ]Causative agent of Brazilian purpuric fever[BPF]Responds to local sulphanamides &gentamicin
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Haemophilus ducreyi
Ducrey demonstrated in chancroid lesionsShort ,ovoid bacillusGram nagative often may appear gram positive& frequently show bipolar staining May be arranged in small groups or whorls or inparallel chains giving aSCHOOL OF FISH or
RAIL ROAD TRACK appearance
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CONT
Can be grown on fresh clotted rabbit bloodMay also grown on chorio allontioc membraneof chick embryo
On choclate agar enriched with isovitalex andfetal calf serum & containing vancomycin as aselective agent
Forms small ,grey ,translucent colonies afterincubation at 35 c under 10 % co2 & highhumidity in 2 8 days
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CONT
Antigenically homogenousCultures may be identified by agglutinatoin
with anti serumSusceptible to sulphonamides & many antibiotics
Erythromycin ,Cotrimoxazole,Ciprofloxacin may be used for treatment
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Choclate agar
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Haemophilus parainfluenzae
Requires factor V & not the factor X Commensel in the upper respiratory tract
Causes bacterial endocarditis ,urethritis,acute pharyngitis
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Haemophilus haemolyticus
Requires both factor X & V Commensal of upper respiratory tract
Strains that donot require factor X havebeen designated as H parahaemolyticus
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Haemophilus aphrophilus
Requires factor X but not factor V Cause bacterial endocarditis ,brain abscess
,sinuisitis pneumoniaStrains requiring factor V but not factor X have been termed as H paraaphrophilus
HACEK b i
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HACEK group bacteriaFastidious slow growing bacteria
H - Haemophilus species
A - ActinobacillusC - Cardiobacterium hominisE - Eikenella corrodens
K Kingella kingae
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