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PSEUDOMONAS

PSEUDOMONAS. Introduction. Large group of aerobic non sporing gram negative motile by polar flagella ubiquitous oppurtunistic infections newer genera-Burkholderia Stenotrophomonas.

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PSEUDOMONAS

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  1. PSEUDOMONAS Introduction

  2. Large group of aerobic non sporing gram negative motile by polar flagella • ubiquitous • oppurtunistic infections • newer genera-Burkholderia Stenotrophomonas

  3. Species • Pseuomonas aeruginosa • Stenotrophomonas maltophila • Burkholderia cepacia • Burkholderia mallei • Burkholderia pseudomallei

  4. 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

  5. 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

  6. Cont.. • Nutrient agar- • Colonies are smooth,large,translucent,low convex,2-4mm in diameter. • Produce sweetish aromatic odour • Greenish blue pigment diffuses

  7. Cont.. • Blood agar • Similar to nutrient agar • Many are haemolytic • Mac conkeyagar • Colourless,non lactose fermenters • Cetrimide agar • selective media

  8. 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

  9. Pyocyanin Pyoverdin

  10. Cont.. • Pyorubin • Reddish brown pigment • Insoluble in chloroform but soluble in water • pyomelanin • Brown to black pigment • Production is uncommon

  11. Biochemical reactions • O/F test-oxidative • Catalase-positive • Oxidase-positive • Nitrate reduction-positive

  12. Cont.. Indole test-negative Methyl red test-negative Vp test-negative Citrate test-positive Urease test-negative

  13. Cont… Sugar fermentation tests Glucose-only acid Lactose-negative Sucrose-negative Mannitol-negative

  14. Resistance Susceptible to heat,killed at 55°c in one hour acids beta glutarldehyde Silver salts strong phenolic disinfectants So,silversulphonamide as a topical cream in burns is used

  15. Cont… Resistant to chemical agents common antiseptics disinfectants -ammonium compoundschlroxylenol hexachlorophane antibiotics -aminoglycosides cephalosporins pencillins

  16. Antigenic structure • O antigens • Possesses 19 distinct,group specific O antigens • Heat labile • H antigens • Two heat labile antigens recognised in Ps.aeruginosa

  17. 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

  18. 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

  19. 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

  20. 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

  21. cont.. • Wound and burn infections • Chronic otitis media and otitis externa • Eye infections • Acute necrotising vasculitis • Infantile diarrhoea

  22. Mechanism Of Pathogenesis • Caused by exotoxins,proteases,elastases,haemolysins,lipases and enterotoxins • Exotoxin A-lethal toxin • Elastases-haemorrhagic lesions • Enterotoxins-diarrhoeal disease • Slime layer acts as a capsule and enhances virulence

  23. Thank you

  24. HAEMOPHILUS INTRODUCTION

  25. HAEMOPHILUS INFLUENZAE MORPHOLOGY SMALL [ 1.0 X 0.3 MICRONS] GRAM NEGATIVE NON MOTILE NON SPORING EXHIBIT PLEOMORPHISM

  26. CULTURAL CHARACTERISTICS FACTOR X FACTOR V HEAT LABILE BACTERIAL VITAMIN ANEROBIC RESPIRATION • HEAT STABLE • HEMIN • AEROBIC RESPIRATION

  27. CONT… AEROBIC GROWS ANEROBICALLY ALSO OPTIMUM TEMPERATURE-37C SOME STRAINS REQUIRE 10% CO2 BLOOD AGAR-SCANTY GROWTH

  28. 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

  29. satellitism

  30. 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

  31. BIOCHEMICAL REACTIONS Catalase-positive Oxidase-positive Glucose,Xylose-fermented with acid production Lactose,Sucrose,Mannitol-not fermented

  32. 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

  33. 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

  34. 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

  35. 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

  36. 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

  37. 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

  38. 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

  39. 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

  40. LAB DIAGNOSIS 1.SPECIMENS • CSF • Blood • Throat swab • Sputum • Pus • Aspirates from joints ,middle ears

  41. 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

  42. CONT..... 3.DIRECT MICROSCOPY • Gram staining • Immunoflouroscence and quellung reaction • Antigen detection • Latex agglutination • Co-agglutination • Counter immuno electrophoresis

  43. CONT… 4.CULTURE • CSF culture • Blood culture • Sputum culture 5.COLONY MORPHOLOGY AND STAINING 6.SEROTYPING

  44. TREATMENT Cefotaxime & Ceftazidime is the drug of choice for meningitis Ampicillin &Cotrimoxazole –respiratory infections Amoxycillin - clavulanate or clarithromycin is more effective

  45. 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

  46. Haemophilusaegyptius 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

  47. Haemophilusducreyi 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

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