Unit 3: Spirochetes Flashcards
How many generas are there of spirochetes?
What are three spirochetes that are clinically significant human pathogens?
8
-Treponema
-Borrelia
- Leptospira
Characteristics of Spirochetes?
Long, slender helically curved Gram-negative bacteria with spiral shape, a flexible cell wall, and motility based on axial filaments
List two difficulties associated with spirochetes in the lab.
Very difficulty to see under the light microscope (very thin) and difficult to cultivate
How big are spirochetes?
5-15 micron in long but only about 0.1 micron wide (so difficulty to be seen under light microscopy
-some are normal inhabitants of oral and genital tract
*do not stain well
-not culturable in vitro
Treponema
-requires moist, dark environment to survive and causes venereal syphilis
-European epidemic in 15th century
- Another epidemic after WWII
T. pallidum subsp. Pallidum
Syphilis occurs in how many stages?
Occurs in three stages: Primary, Secondary and Latent
Describe primary syphilis
painless ulcer (chancre), heals in 3 to 6 weeks and may go unnoticed. The bacteria disseminate during this stage
Describe secondary syphilis
ill, fever, weight loss and skin rash, moth-eaten appearance due to loss of eyebrows. Infected person is very contagious (sexually transmitted disease AND contact disease)
Describe latent syphilis
The person may stay at this stage for a rest of life and not very contagious to others. About 35% of untreated patients will enter a late or tertiary stage 10 to 25 years after infections that are associated with gummas (soft gummy tumors)
What bacteria causes Yaws?
What type of climate is it found in?
T. pallidum subsp. pertenue
Humid, ward climates, mostly under 15 years
How is Yaws transmitted?
Not sexually transmitted, organism enters through traumatized skin
What is the treatment of Yaws?
a single shot of penicillin
What are the stages of Yaws?
-First stage: initial bump (mother yaw)
-Secondary stage: Crops of bumps, swelling lymph glands
-Tertiary stage: destroy skin, bone and joints
What bacteria causes Bejel?
T. pallidum subsp. endemicum
Who and where is Bejal mostly seen in?
-Mostly in children in warm climates
-A endemic non-venereal syphilis
How is Bejel transmitted?
Mouth to mouth transmission, sharing utensils
Symptoms of Bejel?
Begins with a small mucous path, often on the interior of the mouth, followed by the appearances of raised, eroding lesions on the limbs and trunk.
What is Pinta?
-Result in large, scaly, red lesions called pintids
-Does not progress deep into the body (superficial)
What bacteria causes Pinta?
T. carateum
How is Pinta transmitted?
How is Pinta treated?
Not sexually transmitted, through skin abrasions
Penicillin single shot
What bacteria causes Sodoku?
How is is best viewed?
Spirillium minus
Darkfield microscopy**
Sodoku is associated with ___________ fever (similar to S. moniformis)
rat-bite
What are the symptoms of Sodoku?
-Chills, open sore at the site of bite
-Rash- may be red/purple plaques
-Swollen lymph nodes near bite
How is Sodoku treated?
with penicillin
What bacteria causes human relapsing fever (high temp and flulike symptoms every few days)
-worldwide
Borrelia recurrentis
What are the vectors for Borrelia recurrentis?
epidemic- ___________
endemic- ____________
Louse
tick
What causes relapsing fever with Borrelia recurrentis?
because of antigenic variation (spirochetes change surface proteins)
How is Borrelia recurrentis viewed?
under light microscopy if symptoms are present
What bacteria causes Lyme diseases?
What is the vector?
Borrelia burgdorferi
Vector: Ixodes ticks (all stages)
What is the most common vector borne disease in the U.S?
Lyme disease***
What symptoms and conditions can lyme disease cause? (first and later stage)
First stage: erythema migrans (bullseye), usually appears at the site of tick bite
Later stage: arthritis, neurologic disorders, carditis
What testing is done to determine lyme disease? What is a disadvantage?
Serology test: standard (false positives) *bc it can cross-reacts to other spirochetes
IB (immunoblotting): confirm test.
-Zoonotic; excreted in urine of animals
-Can enter through breaks in skins, eye
-Swimming, hunting, canoeing, farmers, ranchers, veterinarians etc.
Leptospira interrogans
What does Leptospira interrogans cause?
leptospirosis: Anicteric and icteric (jaundice)
Difference between Anicteric and Icteric Leptospirosis?
-Anicteric: milder, self-limiting, high fever and headaches 3-7 days (septicemic), followed by immune stage (aseptic meningitis)
-Icteric (Weil’s disease): severe, liver, kidney or vascular dysfunction with pulmonary hemorrhage
What are the two ways Leptospira interrogans is diagnosed?
-microscopy
-serological tests
???
Light microscopy is used for diagnosis of…
Dark field or Fluorescent microscopy is for diagnosis of…
Borrelia, Leptospira, or spirillum
Treponema
detect reaginic Ab developed against lipids released from damaged cells (not specific antigen), e.g. RPR and VDRL test. RPR uses charcoal to visualize flocculation while VDRL uses cardiolipin-cholesterol antigen to detect reaginic antibodies.
Nontreponemal test
-non-specific, non-
diagnostic
What is a positive titer result?
what does a low RPR titer indicate?
-titer 1:2 or more
-therapy completion, early disease, biological false-positives (bc not detecting the bacteria itself)
What can cause Biological false positives (BFPs) when testing for these types of infections?
-Due to tissue damage or cross-reactivity
-Any other spirochetes diseases
-Autoimmune diseases e.g. rheumatoid arthritis or tissue disorders
-Malignant tumors
-Infectious diseases such as mononucleosis, hepatitis, viral infections (e.g. measles, HIV)
Confirmatory tests for syphilis?
Treponemal tests
-Detect Ab specific for
treponemal antigens
What are the two-main treponemal tests used?
FTA-ABS and MHA-TP***
Treponemal test:
Fluorescent treponemal antibody absorption: serum (Ab) mixed with not pathogenic Treponeme strain (Reiter strain) and stained with FITC labeled Ab
FTA-TP
Treponemal test:
MHA-TP?
Microhemagglutination Treponema
Treponemal test:
uses RBCs coated with T. pallidum antigens. Perform in a well.*
Pallidum
What does a positive and negative MHA-TP test look like?
Negative: RBC sediment at bottom
Positive: agglutination
