Susmita.b Indira

7/28/2019 Susmita.b Indira

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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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Susmita.b Indira

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