Spirochaetes

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Spirochaetes
By
Dr. Emad AbdElhameed Morad
Lecturer of Medical Microbiology and Immunology
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• Spirochaetes are long, slender, spiral organisms
  which are motile by periplasmic internal
  flagellae.
• Spirochaetes include three genera

Treponema
Borrelia
Leptospira
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Leptospira
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Species

• Leptospira icterohemorrhagiae is a pathogen in
  rats, rodents , dogs.
• Man is infected from these animals. How?

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Morphology

• Long thin finely coiled spirochaetes.
• One or both ends are hooked.
• It can be seen by dark field microscope.
• It could be stained with Silver, Fontana or
  Giemsa stains.

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Cultural characters

• Aerobic.
• Grow on semisolid media containing rabbit serum
  like Stuarts medium or Fletchers medium.
• Optimum temperature is 30 degree.
• Growth appears after 1-2 weeks.

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Animal pathogenicity

• If the organism is injected intraperitoneal in
  Guinea pig, it will die in 1 or 2 weeks.

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Weils disease

• Mode of infection contact with or drinking
  water contaminated with the excreta of animals
  like rats and dogs.
• Leptospira will enter through abrasions in the
  skin or mucous membranes.
• So, Weils disease occurs in sewage workers,
  miners, fishermen and military persons.

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• Incubation period 1 - 2 weeks.
• After incubation, the patient develops
• Fever for few days (the bacteria is present in
  blood).
• Jaundice.
• Hemorrhage.
• Renal failure.
• Severe cases may develop meningitis.

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Weils disease
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Laboratory diagnosis

• Specimen
• Blood during the first week of fever.
• Urine during 2nd to 4th weeks of fever.
• Direct microscopic examination by
• Dark field microscope.
• After staining by silver or Fontana stain.
• Direct IF

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• Culture
• Stuarts or Fletchers medium.
• At 30 degree.
• Growth appears after 1-2 weeks.
• Animal inoculation
• The most sensitive method.
• Guinea pigs are injected intraperitoneal.
• Die in 1-2 weeks.
• Direct detection of leptospiral DNA in the
• specimen by PCR.

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• Serological diagnosis
• Detection of antibodies (IgM or rising titer of
  IgG)
• Positive during second week of fever.
• By ELISA or agglutination test.

DO NOT FORGET
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Treatment

• Penicillin and doxycycline are effective early
  in infection.

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GOOD LUCK