Exam 5 - Spirochetes

Question 1

List the 3 clinically significant species of spirochetes

Answer 1

• Leptospira species
• Treponema species
• Borrelia species

Question 2

What are the general characteristics of spirochetes?

Answer 2

• Highly motile

- Corkscrew-shaped

Question 3

What are the key reactions of the Leptospira species?

Answer 3

Oxidase (+)

Catalase (+)

Question 4

Describe how Leptospira is seen in the lab.

Answer 4

• Can be seen on Wright-stained smears in hematology
• Stains very poorly on Gram stains
• Can visualize best on darkfield or phase contrast

Question 5

How can you get the best specimens of Leptospira?

Answer 5

• 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

Question 6

What kind of media is used for Leptospira?

Answer 6

It requires specialized media

Question 7

The Leptospira species is a causative agent of what disease?

Answer 7

Leptospirosis

Question 8

Describe Leptospirosis.

Answer 8

• Zoonotic
• Passed through animal urine

- Weil’s disease is the most severe form of Leptospirosis:
       # Jaundice
       # Acute renal failure
       # Hemorrhage
       # Multi-organ failure

Question 9

How is the Leptospira species diagnosed?

Answer 9

• Increased liver enzymes,
• Abnormal urinalysis (including hematuria)
• WBC differential with leukocytosis (shift to immature bands)

Question 10

What does the Treponema species look like?

Answer 10

• Tightly coiled

- Encased in a sheath which can hide its antigens from the host’s immune system

Question 11

How can you see the Treponema species in the lab?

Answer 11

• Does not grow well in the lab

- Can be seen on direct smears using darkfield microscopy

Question 12

How are Treponema specimens obtained?

Answer 12

Specimens are usually obtained directly from the lesion

Question 13

Treponema species are a causative agent of what diseases?

Answer 13

• Syphilis (STD)

- Endemic Treponematoses

Question 14

What are examples of endemic treponematoses?

Answer 14

• Yaws
• Pinta
• Endemic syphilis

Question 15

How are the Treponema species treated?

Answer 15

Treated with Penicillin

Question 16

How are the Treponema species diagnosed?

Answer 16

With serological testing:

- RPR
- VDRL

Question 17

What are unique characteristics of the Borrelia species?

Answer 17

• No sheath
• Can survive in cold-blooded and warm-blooded hosts
• Has antigenic variation
• Has adhesins

Question 18

What is antigenic variation, and how does Borrelia benefit?

Answer 18

The ability to change its antigenic surface proteins to confuse the host’s immune system

Question 19

What are adhesins, and how does Borrelia benefit?

Answer 19

Allows it to adhere to various host tissues

Question 20

The Borrelia species is the causative agent of what diseases?

Answer 20

• Lyme disease

- Relapsing fever

Question 21

How is Lyme disease diagnosed?

Answer 21

With serological testing

Question 22

How is Lyme disease visualized in the lab?

Answer 22

It can be visualized in darkfield microscopy

Question 23

How is relapsing fever diagnosed?

Answer 23

With serological testing

Question 24

How is relapsing fever visualized in the lab?

Answer 24

• Can be visualized on fixed blood smears, usually in hematology
• On a wet prep, can be seen moving around, pushing red cells

Question 25

What kind of media is used for the Borrelia species?

Answer 25

It requires specialized media to be grown in the lab