Micro - Clinical Bacteriology (Gram - Spirochetes)

Question 1

What kind of morphology do spirochetes have? What are examples of spirochetes?

Answer 1

The spirochetes are spiral-shaped bacteria with axial filaments and include: Borrelia (big size), Letospira, and Treponema

Question 2

Which spirochete is the largest?

Answer 2

Borrelia; Think: “Borrelia = Big size”

Question 3

How is Treponema visualized?

Answer 3

Treponema is visualized by dark-field microscopy

Question 4

How can Borrelia be visualized? What is important to know about this visualization?

Answer 4

Only Borrelia (of all spirochetes) can be visualized using aniline dyes (Wright’s or Giemsa stain) in light microscopy

Question 5

What is a source of Leptospira interrogans?

Answer 5

Found in water contaminated with animal urine

Question 6

What main disease/condition does Leptospira interrogans cause? What are the associated symptoms?

Answer 6

Leptospirosis: flu-like symptoms, jaundice, photophobia with conjunctival suffusion (erythema without exudate)

Question 7

Among what population(s) is L. interrogans prevalent?

Answer 7

Prevalent among surfers and in tropics (i.e., Hawaii)

Question 8

What is another name for Weil disease? What are its symptoms? With which pathogen is it associated?

Answer 8

Aka Ictohemorrhagic Leptospirosis = severe form with jaundice and azotemia from liver and kidney dysfunction; Fever, hemorrhage, anemia; Leptospira interrogans

Question 9

What pathogen causes Lyme disease?

Answer 9

Borrelia burgdorferi

Question 10

What is the vector for Borrelia burgdorferi? For what other pathogen is this also the vector?

Answer 10

Ixodes tick; Also vector for Babesia

Question 11

What is the natural reservoir for B. burgdorferi? Why is this significant?

Answer 11

Natural reservoir is the mouse; Mice are important to tick life cycle (recall: Ixodes tick = B. burgdorferi vector)

Question 12

What disease does B. burgdorferi cause? In what geographic location(s) Is it commonly found?

Answer 12

Lyme disease; Common in northeastern United States

Question 13

Again, what pathogen causes Lyme disease? How it is treated?

Answer 13

Borrelia burgdorferi; Doxycycline, Ceftriaxone

Question 14

What are initial versus later symptoms of Lyme disease?

Answer 14

INITIAL SYMPTOMS - erythema chronicum migrans, flu-like symptoms, +/- facial nerve palsy; LATER SYMPTOMS - monoarthritis (large joints) and migratory polyarthritis, cardiac (AV nodal block), neurologic (encephalopathy, facial nerve palsy, polyneuropathy); Think: “FAKE a Key Lyme pie = Facial nerve palsy (typically bilateral), Arthritis, Kardiac block, Erythema migrans.

Question 15

What is the morphology, genus, and species of the pathogen that causes Syphilis?

Answer 15

Caused by spirochete Treponema pallidum

Question 16

What is the treatment for Syphilis?

Answer 16

Penicillin G

Question 17

What kind of disease is Primary Syphilis, and how does it present?

Answer 17

Localized disease presenting with painless chancre

Question 18

How do you screen for and confirm a Primary syphilis diagnosis?

Answer 18

Serologic testing: VDRL/RPR (non-specific), confirm diagnosis with specific test (e.g., FTA-ABS)

Question 19

What kind of disease is Secondary Syphilis, and how does it present?

Answer 19

Disseminated disease with constitutional symptoms, maculopapular rash (palms and soles), condyloma lata (also confirmable with dark-field microscopy); Think: “Secondary syphilis = Systemic”

Question 20

In what kind of patient findings are treponemes actually present, and in what context do such findings occur? How are they visualized?

Answer 20

Treponemes are present in chancres of primary Syphilis and condyloma lata of secondary Syphilis; If available, use dark-field microscopy to visualize treponemes in fluid from chancre (primary syphilis) or condyloma lata (secondary Syphilis)

Question 21

How do you screen for and confirm diagnosis of Secondary Syphilis?

Answer 21

Screen with VDRL and confirm diagnosis with FTA-ABS

Question 22

What are the symptoms/signs associated with Tertiary syphilis?

Answer 22

Gummas (chronic granulomas), aortitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis, “general paresis”), Argyll Robertson pupil; Signs: Broad-based ataxia, Positive Romberg, Charcot joint, Stroke without hypertension

Question 23

What test is used for to test for neurosyphilis?

Answer 23

For neurosyphilis: test spinal fluid with VDRL or RPR

Question 24

What are symptoms/findings associated with Congenital syphilis?

Answer 24

Saber shins, Saddle nose, CN VIII deafness, Hutchinson’s teeth, Mulberry molars

Question 25

What is important to remember in terms of transmission of Congenital syphilis?

Answer 25

To prevent, treat mother early in pregnancy, as placental transmission typically occurs after first trimester

Question 26

What is Argyll Robertson pupil? What is another name for this condition? With what condition is Argyll Robertson pupil associated?

Answer 26

Pupil constricts with accommodation but is not reactive to light; “Prostitute’s pupil”; Associated with Tertiary syphilis

Question 27

What does VDRL detect?

Answer 27

VDRL detects nonspecific antibody that reacts with beef cardiolipin

Question 28

What condition/disease is VDRL used to diagnose?

Answer 28

Syphilis

Question 29

What are the false positives associated with VDRL?

Answer 29

May false positives, including viral infection (mononucleosis [EBV], hepatitis), some drugs, rheumatic fever, and SLE (also, leprosy); Think: “VDRL = Viruses (mono, hepatitis), Drugs, Rheumatic fever, Lupus and Leprosy”

Question 30

What is Jarisch-Herxheimer reaction, and what causes it?

Answer 30

Flu-like syndrome immediately after antibiotics are started, due to killed bacteria releasing pyrogens