Exam 5 - Spirochetes Flashcards
List the 3 clinically significant species of spirochetes
- Leptospira species
- Treponema species
- Borrelia species
What are the general characteristics of spirochetes?
- Highly motile
- Corkscrew-shaped
What are the key reactions of the Leptospira species?
Oxidase (+)
Catalase (+)
Describe how Leptospira is seen in the lab.
- Can be seen on Wright-stained smears in hematology
- Stains very poorly on Gram stains
- Can visualize best on darkfield or phase contrast
How can you get the best specimens of Leptospira?
- Collected during first ten days of illness, while patient has fever
- They will present first week in blood and CSF, after 2-3 weeks in urine
What kind of media is used for Leptospira?
It requires specialized media
The Leptospira species is a causative agent of what disease?
Leptospirosis
Describe Leptospirosis.
- Zoonotic
- Passed through animal urine
- Weil’s disease is the most severe form of Leptospirosis:
# Jaundice
# Acute renal failure
# Hemorrhage
# Multi-organ failure
How is the Leptospira species diagnosed?
- Increased liver enzymes,
- Abnormal urinalysis (including hematuria)
- WBC differential with leukocytosis (shift to immature bands)
What does the Treponema species look like?
- Tightly coiled
- Encased in a sheath which can hide its antigens from the host’s immune system
How can you see the Treponema species in the lab?
- Does not grow well in the lab
- Can be seen on direct smears using darkfield microscopy
How are Treponema specimens obtained?
Specimens are usually obtained directly from the lesion
Treponema species are a causative agent of what diseases?
- Syphilis (STD)
- Endemic Treponematoses
What are examples of endemic treponematoses?
- Yaws
- Pinta
- Endemic syphilis
How are the Treponema species treated?
Treated with Penicillin
How are the Treponema species diagnosed?
With serological testing:
- RPR - VDRL
What are unique characteristics of the Borrelia species?
- No sheath
- Can survive in cold-blooded and warm-blooded hosts
- Has antigenic variation
- Has adhesins
What is antigenic variation, and how does Borrelia benefit?
The ability to change its antigenic surface proteins to confuse the host’s immune system
What are adhesins, and how does Borrelia benefit?
Allows it to adhere to various host tissues
The Borrelia species is the causative agent of what diseases?
- Lyme disease
- Relapsing fever
How is Lyme disease diagnosed?
With serological testing
How is Lyme disease visualized in the lab?
It can be visualized in darkfield microscopy
How is relapsing fever diagnosed?
With serological testing
How is relapsing fever visualized in the lab?
- Can be visualized on fixed blood smears, usually in hematology
- On a wet prep, can be seen moving around, pushing red cells
What kind of media is used for the Borrelia species?
It requires specialized media to be grown in the lab
