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PSEUDOMONAS
Introduction
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Large group of aerobic non sporing gram negative motile by polar flagellaubiquitousoppurtunistic infectionsnewer genera-Burkholderia Stenotrophomonas
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SpeciesPseuomonas aeruginosaStenotrophomonas maltophilaBurkholderia cepaciaBurkholderia malleiBurkholderia pseudomallei
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Pseudomonas aeruginosaMorphologyslender,Gram negative bacillussize-1.5 microns-3*1.5micronsmotile by polar flagellanon capsulated though some mucoid strains may sometimes occursome are pilated
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Cultural characteristicsObligate aerobeWide range of temperature 5c-42c optimum 37cOrdinary media large,opaque,irregular,with distinctive musty,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 agarSimilar to nutrient agar Many are haemolyticMac conkey agarColourless,non lactose fermentersCetrimide agar selective media
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Pigment productionPyocyaninBluish green phenazine pigment Soluble in chloroform and waterNot produced by other speciesPyoverdin(fluorescin)It is a greenish yellow pigment Insoluble in chloroform but soluble in waterProduced by many other species
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Pyocyanin Pyoverdin
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Cont..PyorubinReddish brown pigment Insoluble in chloroform but soluble in waterpyomelaninBrown to black pigmentProduction is uncommon
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Biochemical reactionsO/F test-oxidativeCatalase-positiveOxidase-positiveNitrate reduction-positive
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Cont..Indole test-negativeMethyl red test-negativeVp test-negativeCitrate test-positiveUrease test-negative
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ContSugar fermentation testsGlucose-only acid Lactose-negativeSucrose-negativeMannitol-negative
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ResistanceSusceptible to heat,killed at 55c in one houracidsbeta glutarldehydeSilver saltsstrong phenolic disinfectantsSo,silver sulphonamide as a topical cream in burns is used
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ContResistant to chemical agents common antiseptics disinfectants -ammonium compounds chlroxylenolhexachlorophane antibiotics -aminoglycosides cephalosporins pencillins
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Antigenic structureO antigensPossesses 19 distinct,group specific O antigensHeat labileH antigens Two heat labile antigens recognised in Ps.aeruginosa
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Toxins and enzymesExtracellular products Pyocyanin inhibits mitochondrial enzymes and causes disruption and cessation of ciliary beat on ciliated nasal eptheliumExtracellular 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 typingThree types of bacteriocins are produced-R,F,SPyocin produced by test strain is employed to assess 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 with pulsed-field gel electrophoresis(PAGE) is most reliableCont..
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PATHOGENESISImportant agent in causing nosocomial infectionsMost common infections are Urinary tract infections following catheterisationAcute purulent meningitis following lumbar puncturePost-tracheostomy pulmonary infectionSepticaemia in debilitated patients
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cont..Wound and burn infectionsChronic otitis media and otitis externaEye infectionsAcute necrotising vasculitis Infantile diarrhoea
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Mechanism Of PathogenesisCaused by exotoxins,proteases,elastases,haemolysins,lipases and enterotoxinsExotoxin A-lethal toxinElastases-haemorrhagic lesions Enterotoxins-diarrhoeal diseaseSlime layer acts as a capsule and enhances virulence
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Thank you
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HAEMOPHILUSINTRODUCTION
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HAEMOPHILUS INFLUENZAEMORPHOLOGYSMALL [ 1.0 X 0.3 MICRONS]GRAM NEGATIVENON MOTILENON SPORINGEXHIBIT PLEOMORPHISM
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CULTURAL CHARACTERISTICSFACTOR XHEAT STABLE
HEMIN
AEROBIC RESPIRATIONFACTOR VHEAT LABILE
BACTERIAL VITAMIN
ANEROBIC RESPIRATION
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CONTAEROBICGROWS ANEROBICALLY ALSOOPTIMUM TEMPERATURE-37CSOME STRAINS REQUIRE 10% CO2BLOOD AGAR-SCANTY GROWTH
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SATELLITISMStaph.aureus is streaked across a plate of blood agar on which a specimen containing H.influenzae has inoculatedAfter overnight incubation-Colonies large -along the streak of Staph.aureus small farther away
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satellitism
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CONTLEVINTHAL`S MEDIUMBoiling and filtering a mixture of blood and nutrient brothCapsulated strains produce translucent coloniesFILDES AGARBy adding a peptic digest of blood to nutrient agarBest for primary isolationCopious growth
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BIOCHEMICAL REACTIONSCatalase-positive
Oxidase-positive
Glucose,Xylose-fermented with acid production
Lactose,Sucrose,Mannitol-not fermented
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RESISTANCEDestroyed by heating refrigeration drying disinfectantsCultures may be preserved for about a month on choclate agar slopes in screw capped bottlesLong term preservation culture may be lyophilised
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ANTIGENIC PROPERTIES3 Major surface antigens Capsular polysaccharide Outer membrane protien Lipo 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 strainType b strain contains pentose sugars ribose &ribitol instead of hexoses & hexosamines in other 5 serotypesCapsular polyribosyl ribitol phosphate antigen of Hib induces IgG IgM IgA antibodies which are bactericidal and protective
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CONT.Strains lacking a capsule cannot be typed and are called NON TYPABLE STRAINSOuter membrane protein antigens of H influenzae type b have been classified into 13 sub typesLipo oligosaccharides are antigenically complex
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PATHOGENECITYExclusively human pathogen Not pathogenic for animals but intra peritoneal inoculation of large doses is fatal in mice,guinea pigs &rabbitsDiseases due to H influnzae considered under 2 groups invasive and non invasive
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INVASIVESpread through Blood
Meningitis,arthritis, endocardits,conjuctivitis,pancarditis
Seen in children
Caused by capsulated strains NON INVASIVE Spread through local invasion
Otitis media,sinusitis
Seen in adults
Caused by non capsulated strains
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CLINICAL MANIFESTATIONSMENINGITISBacilli reach meninges from nasopharynx through blood streamCommon in children
LARYNGO EPIGLOTTISAcute inflammaton of epiglottis with obstructive laryngitisChildren above 2 years
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CONT.PNEUMONIAInfants accompanied by empyemaOlder children & adults by lobar pneumonia These are primary infections due to capsulated strainsBroncho pneumonia may occur as secondary infection due to non capsulated strains
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CONTSUPPURATIVE LESIONSArthritis,endocarditis& pericarditis may result from hematogenous disseminationOtitis media occurs by direct spread from nasopharynxBRONCHITISAssociated with pneumococci in acute exacerbationof chronic bronchitis &bronchiectasis
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LAB DIAGNOSIS1.SPECIMENSCSFBlood Throat swabSputumPus Aspirates from joints ,middle ears
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2.COLLECTION &TRANSPORTCollected in sterile containers & under aseptic conditionsVery sensitive to low temp so should not be refrigeratedTransported to laboratory with out delayInoculated on culture media immediately
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CONT.....3.DIRECT MICROSCOPYGram stainingImmunoflouroscence and quellung reactionAntigen detectionLatex agglutinationCo-agglutinationCounter immuno electrophoresis
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CONT 4.CULTURECSF cultureBlood cultureSputum culture5.COLONY MORPHOLOGY AND STAINING6.SEROTYPING
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TREATMENTCefotaxime & Ceftazidime is the drug of choice for meningitisAmpicillin &Cotrimoxazole respiratory infectionsAmoxycillin - clavulanate or clarithromycin is more effective
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EPIDEMIOLOGY & PREVENTIONInfection transmitted by respiratory routeImmunity is type specific Active immunization with Hib PRP vaccine is indicatedConjugate Hib PRP is used for younger childrenRifampicin -4 days prevents secondary infection in contacts & also eradicates carrier state
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Haemophilus aegyptiusKOCH WEEKS BACILLUSNon capsulatedCauses highly contagious form of conjuctivitis [ pink eye ]Causative agent of Brazilian purpuric fever [BPF] Responds to local sulphanamides & gentamicin
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Haemophilus ducreyiDucrey demonstrated in chancroid lesionsShort ,ovoid bacillus Gram nagative often may appear gram positive & frequently show bipolar stainingMay be arranged in small groups or whorls or in parallel chains giving a SCHOOL OF FISH or RAIL ROAD TRACK appearance
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CONTCan be grown on fresh clotted rabbit bloodMay also grown on chorio allontioc membrane of chick embryoOn choclate agar enriched with isovitalex and fetal calf serum & containing vancomycin as a selective agentForms small ,grey ,translucent colonies after incubation at 35 c under 10 % co2 & high humidity in 2 8 days
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CONTAntigenically homogenous Cultures may be identified by agglutinatoin with anti serumSusceptible to sulphonamides & many antibioticsErythromycin ,Cotrimoxazole ,Ciprofloxacin may be used for treatment
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Choclate agar
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Haemophilus parainfluenzaeRequires factor V & not the factor XCommensel in the upper respiratory tract Causes bacterial endocarditis ,urethritis ,acute pharyngitis
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Haemophilus haemolyticusRequires both factor X & VCommensal of upper respiratory tractStrains that donot require factor X have been designated as H parahaemolyticus
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Haemophilus aphrophilusRequires 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
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HACEK group bacteriaFastidious slow growing bacteria H - Haemophilus species A - Actinobacillus C - Cardiobacterium hominis E - Eikenella corrodens K - Kingella kingae
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