Lec 18 Spirochaetales.ppt

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Lec 18 Spirochaetales.ppt

  1. 1. Spirochaetales The Spirochetes
  2. 2. Spirochaetales <ul><li>Classification Spirochetes are members of the order Spirochaetales which contains 2 families </li></ul><ul><ul><li>Spirochaetaceae – contains 2 medically important genera </li></ul></ul><ul><ul><ul><li>Treponema </li></ul></ul></ul><ul><ul><ul><li>Borrelia </li></ul></ul></ul><ul><ul><li>Leptospiraceae – 1 medically important genus </li></ul></ul><ul><ul><ul><li>Leptospira </li></ul></ul></ul><ul><li>Morphology and general characteristics </li></ul><ul><ul><li>Is composed of: </li></ul></ul><ul><ul><ul><li>A helical protplasmic cylinder with a peptidoglycan layer similar to G-B, cytoplasmic membrane, and cytoplasm </li></ul></ul></ul>
  3. 3. Spirochaetales <ul><ul><ul><li>A multilayered outer membrane that surrounds the cylinder </li></ul></ul></ul><ul><ul><ul><li>Periplasmic flagella which are attached to each end of the protoplasmic cylinder and extend toward the opposite end. </li></ul></ul></ul><ul><ul><ul><ul><li>Are not typical flagella and are often called axial filaments </li></ul></ul></ul></ul>
  4. 4. Spirochaetales <ul><ul><li>None of the pathogenic Treponemes have been successfully cultured on artificial media </li></ul></ul><ul><ul><ul><li>T. pallidum is usually cultured in the testes of rabbits, although it has been grown in tissue culture for short periods of time. </li></ul></ul></ul><ul><ul><ul><li>T. pallidum does not survive for long outside the host. </li></ul></ul></ul><ul><ul><ul><li>Visualized by darkfield microscopy or iron staining </li></ul></ul></ul>
  5. 5. T. pallidum
  6. 6. Spirochaetales <ul><ul><li>Borrelia may be grown on a complex media called Kelly’s media, but this is not usually done in diagnostic labs. </li></ul></ul><ul><ul><ul><li>Borrelia may be observed with darkfield microscopy or be stained in a blood sample with a Giemsa stain or Wright stain. </li></ul></ul></ul>
  7. 7. Borrelia sp. in blood smear
  8. 8. Spirochaetales <ul><ul><li>Leptospira can be grown on semi-solid media containing peptone, beef extract supplemented with rabbit serum or bovine serum albumin and tween 80. </li></ul></ul><ul><ul><ul><li>Incubation may be for as long as 28 days. </li></ul></ul></ul><ul><ul><ul><li>Visualize using darkfield microscopy </li></ul></ul></ul><ul><li>Identification </li></ul><ul><ul><li>Treponema </li></ul></ul><ul><ul><ul><li>Observation of organisms in lesions </li></ul></ul></ul><ul><ul><ul><li>Detection of antibodies made in the host. </li></ul></ul></ul><ul><ul><ul><ul><li>Two types of tests may be used: </li></ul></ul></ul></ul>
  9. 9. Spirochaetales <ul><ul><ul><ul><li>Nonspecific, nontreponemal tests – used for screening purposes </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Very sensitive, but not specific </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Many diseases give positive results </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Is inexpensive and easy to do </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Detects non-treponemal antibodies, called reagenic or Wasserman antibodies, that react with a phospholipid (cardiolipin-lecithin) that is a normal tissue constituent </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Tests include: VDRL test, rapid plasma reagin card tests (RPR), and automated reagin test (ART) </li></ul></ul></ul></ul></ul>
  10. 10. Spirochaetales <ul><ul><ul><ul><li>Specific, treponemal tests – used to confirm positive nontreponemal results </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Very specific, expensive, and more difficult to perform </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Include T. pallidum immobilization tests, Fluorescent Treponemal antibody absorption test, indirect Treponemal hemagglutination test </li></ul></ul></ul></ul></ul><ul><ul><li>Borrelia </li></ul></ul><ul><ul><ul><li>Demonstration of Spirochetes in the blood </li></ul></ul></ul><ul><ul><li>Leptospira </li></ul></ul><ul><ul><ul><li>Isolate and culture </li></ul></ul></ul><ul><ul><ul><li>Specific agglutination test or C’ fixation test – look for 4-fold rise in titer in patient’s antibodies against the organism </li></ul></ul></ul>
  11. 11. Spirochaetales <ul><li>Virulence factors </li></ul><ul><ul><li>Treponema </li></ul></ul><ul><ul><ul><li>Molecular mimicry – the outer sheath contains molecules that resemble the molecules commonly found on the surface of human cells. </li></ul></ul></ul><ul><ul><ul><ul><li>This allows the organism to resist host defenses. </li></ul></ul></ul></ul><ul><ul><ul><li>Hyaluronidase </li></ul></ul></ul><ul><ul><li>Borrelia </li></ul></ul><ul><ul><ul><li>Antigenic variation </li></ul></ul></ul>
  12. 12. Spirochaetales <ul><ul><li>Leptospira </li></ul></ul><ul><ul><ul><li>Unknown </li></ul></ul></ul><ul><li>Clinical significance </li></ul><ul><ul><li>Treponema </li></ul></ul><ul><ul><ul><li>T. pallidum causes venereal (transmitted by sexual contact) and non-venereal (transmitted by directly by non-sexual contact, and indirectly by common usage of eating and drinking utensils) syphilis. </li></ul></ul></ul><ul><ul><ul><ul><li>In venereal syphilis the primary lesion is on the genitals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>In non-venereal syphilis it is on oral mucous membranes. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The normal untreated course of the disease occurs in several stages: </li></ul></ul></ul></ul>
  13. 13. Spirochaetales <ul><ul><ul><ul><li>Primary stage – following penetration of the skin or mucous membranes, a characteristic, painless hard chancre develops at the site of entry within 3 weeks. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>The chancre is highly contagious and filled with Treponemes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Simultaneously the organism enters the lymphatics and becomes disseminated. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>The chancre heals without treatment in a few weeks due to local immunity, but by that time the organism has already disseminated. </li></ul></ul></ul></ul></ul>
  14. 14. Primary syphilis
  15. 15. Spirochaetales <ul><ul><ul><ul><li>Secondary stage – 4-8 weeks after the primary stage, the secondary stage develops. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Typically there are lesions (filled with treponemes) throughout the body including the skin, mucous membranes, organs, and eyes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Most lesions are on the skin and mucous membranes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>The patient may also have a loss of hair, a mild fever, and the development of malaise. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>This also heals without treatment and the patient may either spontaneously get well or develop a latent infection </li></ul></ul></ul></ul></ul>
  16. 16. Secondary syphilis
  17. 17. Secondary syphilis
  18. 18. Spirochaetales <ul><ul><ul><ul><li>Latent infection – during this stage there are no symptoms, but specific anti-treponemal antibodies are found. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>This stage may last 3-10 years. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>During this time these is a biological balance between the organism and the host. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>1/3 to ½ may eventually progress to the next stage. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Tertiary syphilis – this stage is characterized by granulomatous lesions, called gummas, of the skin, internal organs, CNS, bones, eyes, and cardiovascular system. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>They are cause by the body’s hyperimmune reaction to remaining spirochetes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>When lesions develop in the CNS it is called neurosyphilis and it can lead to paralysis. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>In the eyes it can lead to blindness </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>In the heart it can lead to aortic damage or aneurisms. </li></ul></ul></ul></ul></ul>
  19. 19. Tertiary syphilis - gummas
  20. 20. Spirochaetales <ul><ul><ul><ul><li>Congenital syphilis – occurs when the treponemes cross the placenta during the fifth month to infect the unborn fetus (occurs usually when mom is in the latent stage). </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>This can result in damage to mental development or other neurological symptoms or the child may be born with generalized syphilis. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>In a pregnant woman who has a primary or secondary stage of the disease, this usually results in stillbirth. </li></ul></ul></ul></ul></ul><ul><ul><ul><li>T. pertenue - causes Yaws or tropical syphilis which transmitted by non-venereal direct contact. </li></ul></ul></ul><ul><ul><ul><li>T. carateum – causes Pinta, a skin disease with hyperpigmentation in patches. </li></ul></ul></ul>
  21. 21. Spirochaetales <ul><ul><li>Borrelia – are arthropod transmitted Spirochetes and they cause: </li></ul></ul><ul><ul><ul><li>Relapsing fever – two types: </li></ul></ul></ul><ul><ul><ul><ul><li>Epidemic – is caused by B. recurrentis and is transmitted by human lice. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>This is a more severe form of the disease than the endemic form. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Endemic – is caused by many Borrelia species and is transmitted by ticks </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Both types of relapsing fever follow the same clinical pattern. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>12-15 days after infection there is an abrupt onset of fever, headache, and myalgia for 4-10 days. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Antibodies are formed and the number of organisms decrease. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>This leads to an afebrile period for a few days to several weeks </li></ul></ul></ul></ul></ul>
  22. 22. Spirochaetales <ul><ul><ul><ul><li>The fever then relapses because the organism has undergone antigenic variation. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The antibodies are no longer effective and the organism numbers increase. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Several relapses may occur with each one being less severe than the previous one. </li></ul></ul></ul></ul><ul><ul><ul><li>Lyme disease – caused by Borrelia burgdorferi and transmitted by ticks. </li></ul></ul></ul><ul><ul><ul><ul><li>This is a systemic illness that may begin with the appearance of a red skin lesion called erythema chronicum migrans (ECM) because the lesion expands in a circular manner. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The patient may also have a fever, headache, nausea, vomiting, myalgia, and fatigue. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>If untreated, the patient may develop arthritis (acute or chronic), and cardiac or neurologic complications weeks or months later due to immune complexes . </li></ul></ul></ul></ul>
  23. 23. Lyme disease
  24. 24. ECM – from Lyme disease
  25. 25. Spirochaetales <ul><ul><li>Leptospira – L. interrogans causes Weil’s disease or leptospirosis </li></ul></ul><ul><ul><ul><li>This disease is acquired by contact with the urine of an infected animal or ingestion of contaminated food or water. </li></ul></ul></ul><ul><ul><ul><ul><li>It is more a disease of animals other than man. </li></ul></ul></ul></ul><ul><ul><ul><li>Infection can vary from asymptomatic to fulminant. </li></ul></ul></ul><ul><ul><ul><li>The CNS, liver, and kidneys are most commonly infected. </li></ul></ul></ul>
  26. 26. Spirochaetales <ul><ul><ul><li>In most cases the incubation is 2-20 days followed by fever, chills, severe headache, myalgia, malaise, nausea and vomiting. </li></ul></ul></ul><ul><ul><ul><li>Jaundice occurs in severe cases </li></ul></ul></ul><ul><ul><ul><li>Death may occur due to renal failure. </li></ul></ul></ul><ul><ul><li>Antibiotic therapy/treatment </li></ul></ul><ul><ul><ul><li>Treponema – penicillin, tetracycline, or erythromycin </li></ul></ul></ul><ul><ul><ul><li>Borrelia - for relapsing fever use tetracycline or erythromycin; for Lyme disease use amoxicillin or doxycycline </li></ul></ul></ul><ul><ul><ul><ul><li>Use protective clothing and repellents to prevent infection </li></ul></ul></ul></ul><ul><ul><ul><li>Leptospirosis provide supportive care; antibiotics (penicillin or erythromycin) are only effective if given during the first 2-4 days of illness </li></ul></ul></ul>

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