spirochetes Flashcards
SPIROCHETES
- large, heterogeneous group of spiral, motile bacteria
- Spirochaetaceae
▫ Treponema
▫ Borrelia - Leptospiraceae
▫ Leptospira
SPIROCHETES
- long, slender, helically coiled, spiral, or corkscrew-shaped bacilli
- endoflagella (axial filaments)
▫ flagella-like organelles in the periplasmic space encased by the outer membrane
▫ begin at each end of the organism and wind around it, extending to and
overlapping at the midpoint
- reproduce by transverse fission
Treponema pallidum
- motile, rotating steadily around their endoflagella even after attaching to cells by their tapered ends
- viewed by darkfield microscopy
- has never been cultured
Treponema pallidum Antigenic Structure
- Hyaluronidase
- Cardiolipin
Treponema pallidum Clinical Findings
- Venereal
▫ Syphilis - Non-venereal
▫ Bejel
▫ Yaws
Treponema pallidum Clinical Findings:
Acquired Syphilis:
- Primary (2-10 wks after infection)
▫ Hard chancre – ulcer with a clean, hard base
▫ Intrarectal, perianal, or oral
▫ Always heals - Secondary (2-10 wks later)
▫ Red maculopapular rash
▫ Condyloma lata - moist, pale papules in the
anogenital region, axillae, and mouth
▫ Meningitis, chorioretinitis, hepatitis, nephritis, or periostitis
▫ Subsides spontaneously - Latent – up to 10 yrs
- Tertiary
▫ Gummas – granulomatous lesion in the skin, bones, and liver
▫ Neurosyphilis – degenerative changes in the central nervous system
▫ Aortic aneurysm, aortic valve insufficiency
Treponema pallidum Clinical Findings:
Congenital Syphilis
- intrauterine infection @ 10th–15th wks AOG
- miscarriage, stillbirth
- Hutchinson’s triad: Hutchinson’s teeth, interstitial keratitis, sensorineural hearing loss
- saddlenose, periostitis, and CNS anomalies
- saber shin
- scaphoid scapula
Treponema pallidum Diagnosis
- Nontreponemal tests – screening test; measure antibodies to
cardiolipin (released by damaged cells)
▫ Rapid plasma reagin (RPR)
▫ Toluidine red unheated serum test (TRUST) - Treponemal tests – confirmatory test; measure antibodies against
T. pallidum antigens
▫ T. pallidum-particle agglutination (TP-PA)
▫ Fluorescent treponemal antibody adsorbed (FTA-ABS)
Treponema pallidum Treatment
- Penicillin G
▫ Jarisch-Herxheimer Reaction
response to lipoproteins released by dying T. pallidum organisms
fever, chills, myalgia, headache, tachycardia, tachypnea, neutrophilia,
and vasodilation with mild hypotension
self-limiting
- What drugs was synthesized by Paul Ehrlich for syphilis? Salvarsan /Arsphenamine
Treponema pallidum Clinical Findings: Bejel
- caused by T. pallidum ssp. endemicum
- a.k.a. endemic syphilis
- Transmission: shared utensils
- oral lesions (chancre), oral papules, gummas (granulomas) of skin, bones,
and nasopharynx
Treponema pallidum Clinical Findings: Yaws
- caused by T. pallidum ssp. pertenuae
- Transmission: direct contact
- ulcerating papule usually on the arms or legs; destructive lesions of skin, lymph nodes, and bones
Borrelia recurrentis
- Transmission: human body louse
- Clinical Findings: Relapsing Fever
▫ due to antigenic variation
▫ sudden onset, with chills and an abrupt rise of temperature
▫ fever declines, followed by a second attack of chills, fever, intense
headache, and malaise
▫ 3-10 recurrences
▫ Bacteria is in the blood during febrile stages, but not during afebrile ones.
Borrelia burgdorferi
- Transmission: Ixodes tick
- adheres to proteoglycans
- Clinical Findings: Lyme Disease
▫ Stage 1: erythema migrans (flat reddened area, which slowly expands,
with central clearing), flu-like symptoms
▫ Stage 2: arthralgia, arthritis, meningitis, facial nerve palsy, cardiac disease
▫ Stage 3: chronic skin, nervous system, or joint involvement
Leptospira interrogans
- tightly coiled, thin, flexible motile spirochetes, with very fine spirals, one end is often bent, forming a hook
- viewed by darkfield microscopy
Leptospira interrogans Transmission
- worldwide zoonosis (domestic or
wild animals)
▫ Main Sources: rats, mice, wild
rodents, dogs, swine, and cattle
▫ shed bacteria in the urine - Transmission:
▫ from leptospires in bodies of water
▫ through breaks in the skin (cuts and
abrasions) and mucous membranes
(mouth, nose, conjunctivae)
