spirochetes Flashcards
spirochete morphology and structure
- elongated, flexible, motile
- spirally wound flagella anchored at poles
- binary fission
- gram-negative
three groups of spirochetes
- treponema
- borrelia
- leptospira
diseases caused by treponema
- syphilis
- yaws
- pinta
diseases caused by borrelia
- relapsing fever
- Lyme Disease
diseases caused by leptospira
leptospirosis
how can treponema pallidum be viewed?
- too small for gram stain
- darkfield microscopy
- immunofluorescence
- silver salts
- electron microscopy
treponema pallidum storage and culture
- can not be grown in culture
- can be kept alive in rich media under anaerobic condition
- survive in blood 24 hours
- survive in tissue for several days
treponema pallidum transmission
- direct contact of genitalia/mucous membranes
- not transmissible in late stages
- mother to fetus (congenital syphilis), still birth, abortion
- rare: transfusion, or contact
treponema pallidum pathogenesis
- incubation 2-6 weeks but bacteria present and replicating
- primary lesion - 1-4 weeks after infection on genitalia
- secondary lesion - after dissemination, generalized skin rash 2-20 weeks post primary lesion
- tertiary lesion - late in disease many years after infection in CNS, rubbery, called “gumma”
treponema pallidum diagnosis
- pathogenic signs
- history of exposure
- organisms in lesion
- positive tests
treponema pallidum tests
- nonspecific (VDRL, flocculation)
- FTA-ABS
- micro hemagglutination test
- ELISA
- TPI
syphilis false positives and negatives
- may read positive in presence of mono or malaria
- ## VDRL has more false results than FTA-ABS
what test is specifically not used for treponema pallidum?
PCR - no specific primers at diagnostic level
antibiotics for treponema pallidum
- very sensitive to penicillin
- tetracycline, erythromycin
vaccine for treponema pallidum?
no vaccine
Yaws, cause and description
- Treponema pertenue
- non-venereal, only through open sores
- often in children
- patients show positive syphilis test
- no placental transmission
- primary lesion resembles raspberry (yaws)
Bejel, cause and description
- Treponema pallidum subspecies endemicum
- similar to yaws
- children in Syria
- treat with penicillin
Pinta, cause and description
- Treponema carateum
- central and south america
- flat, non-ulcerating skin lesions of hands, feet, scalp, leaving depigmented areas after healing
- treat with penicillin
Lyme disease reservoir and vector
- white footed mouse reservoir
- deer tick vector
relapsing fever pathogenesis
- several Borrelia spirochete species
- fever 4-5 days, afebrile 7-10 days, then recurrence and disappearance of fever again. 3-10 relapses total.
Lyme Disease caused by:
Borrelia burgdorferi
Lyme Disease pathogenesis
stage one: papule with expanding erythema 3-14 days after bite, fever, headache, stiff neck, malaise
stage two: neurologic and cardiac involvement
stage three: migrating arthritis weeks to months after bite
Lyme disease diagnosis:
- difficult to isolate organism
- clinical diagnosis mostly
- ELISA test to detect antibodies against B. burgdorferi is available
lyme disease complications/late manifestations
- chronic arthritis
