Spirochaetes

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Spirochaetes

  1. 1. 4.3 Spirochaetes
  2. 2. Background.. Gram negative Motile organismTightly coiled bacteria typically slender and flexouas shape.The cell made up of protoplasmic cylinder located in periplasm of cell, endoflagella and outer sheath.Move by bending and rotating body according to the viscosity of the medium
  3. 3. Motility of spirochetesUnusual mode of motilityEndoflagellum located at one end and extends about two-third of the cell. Its rotate.Protoplasmic cylinder is rigid, whereas the outer sheath is flexible, therefore when both endoflagella rotates in the same direction while protoplasmic cylinder in opposite direction causing torsion of cell.
  4. 4. Medical important3 genera:1. Treponema2. Leptospira3. Borrelia
  5. 5. Treponema•Treponema pallidum pallidum, which causes syphilis•T. pallidum endemicum, which causes bejel or endemicsyphilis•T. pallidum carateum, which causes pinta•T. pallidum pertenue, which causes yaws
  6. 6. YAWS PINTA SYPHILIS
  7. 7. Normal habitatHost associated spirochetes are parasites of humans or animals.Found in lesion of treponematosesCan also found in mucous membranes in the mouth and genital tract, also in skin ulcers
  8. 8. Pathogenicity (T.pallidum)1. Acquired syphilis transmitted congenitally or sexual intercourse - Known as sexually acquired syphilis and congenitally acquired syphilis2. Non-venereal syphilis – endemic syphilis, bejel, njovera, siti and dichuchwa
  9. 9. MicroscopySmall 6-15µm size, 0.2µm diameter.Motile spirochaetes.Use metallic silver techniques or known as impregnation techniques. Metallic silver precipitates on the wall of the spirochete, enlarging its outline and making it opaque, features that make it visible in tissue sections.Best seen by dark-field illumination or phase contrast
  10. 10. CultureMicroaerophilicHardly to grow in routine cultureAble to survive in some fluid including citrated whole bloodMaintained by intratesticular inoculation in rabbit.
  11. 11. Serology testsCardiolipin antigens testVDRL test – Venereal Diseases Reference LaboratoryRPR test – Rapid Plasma ReaginTreponemal antigen testTPHA test (Treponema pallidum haemagglutination test)
  12. 12. LeptospiraScanning electron micrograph of anumber of Leptospira sp. bacteriaatop a 0.1 µm polycarbonate filter Leptospira interrogans
  13. 13. Normal HabitatGram negative, obligate aerobe spirochete.Variety in domestic and wild animals such as rats, rodents, cattle, pigs and dogs. Humans are accidental host.Largely secreted in urineSurvive many weeks in soil and water, in alkaline and 28 – 32oC
  14. 14. TransmissionDirect or indirect contact with urine of infected animalEnter damaged skin which has immersed for a long time in water or mud contaminated with infected urinem/o penetrate the lining of the mouth, nose and eyesPerson to person transmission rarely occurs
  15. 15. Risk factorsPerson most at risk of infection include workers in rice fields and sugar-cane fields, livestock farmers, irrigation canal workers, meat and animal handlers, fresh water fish pond workers, veterinarians, pest control officers, forest workers and those involved in road buildingHigh cases in rainy seasons and times of flooding
  16. 16. PathogenicityMild form usually misdiagnosed as viral illness and influenzaMore serious infection causing a high continuous fever, severe headaches and body pain especially in the muscles of legs, redness of the eye and weakness.Can also causing jaundice and renal failure
  17. 17. MicroscopySmall 6-20µm in size 0.1 µm diameterActively motile spirochetesScrew-tight coils and hooked endsEasily stain only by impregnation techniquesBest seen by dark-field illumination or phase contrast
  18. 18. CultureLeptospires are strictly aerobesCan be cultured in a serum or albumin-Tween mediumLate grow so resulting less efficient diagnosticPreferable serology test to identify several serogroups
  19. 19. Other testsHaematological and biochemical tests in leptospirosisAntimicrobial sensitivity – high doses of penicilin will be effective against L. interrogansELISA test, Polymerase Chain Reaction (PCR)
  20. 20. Borrelia Borrelia burgdoferi Borrelia recurrentis Borrelia duttoni
  21. 21. Normal habitatB.burgdorferi – deer tick,Ixodes scapularis.B.recurrentis – parasite of Pediculus liceB.duttoni – parasite of Ornithodorus soft ticks
  22. 22. PathogenicityB.burgdorferi– causing Lyme Disease.B.recurrentis – louse-bourne relapsing fever in poverty, overcrowding, and during time of drought and famine.B.duttoni – tick-bourne relapsing fever infecting CSF causing lyphocytic meningitis
  23. 23. MicroscopyLarge 10-20µm in size,0.5µm diameterActively motile spirochaetes wt coils of varying sizeAgglutinate togetherEasily stain in Giemsa, Field’s or other Romanowsky stain; prolonged Gram staining (Gram negative)Well seen by dark-field illumination
  24. 24. CultureBorreliae are aerobesCan be cultured in Kelly’s medium
  25. 25. Serology testUsed to diagnose relapsing fever, usually cross reaction with Treponema Antimicrobial sensitivitySensitive to penicillin and tetracycline
  26. 26. THE END

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