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13. spirochetes
spirochetes/microbiology
40
Microbiology
Graduate
02/27/2010

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Term
What are two things unique about spirochetes?
Definition
1. Surrounded by an additional phospholipid-rich outer membrane with few exposed proteins (protection from immune recognition)
2. Periplasmic flagella: enable rotation
Term
How to identify spirochetes?
Definition
Darkfield microscopy, immunofluorescence, silver stain.
Term
Can you culture spirochetes? Identify under the light microscope?
Definition
* No.
* No, too small for LM.
Term
What are 3 genera for spirochetes?
Definition
1. Treponema
2. Borrelia
3. Leptospira
Term
What is the mechanism of pathology for treponemes (a type of spirochetes)?
Definition
Host's own immune response (treponemes do not have known toxins or tissue destructive enzymes)
Term
What causes syphilis?
Definition
Treponema pallidum
Term
In primary syphilis, ulcer erupts 3 - 6 weeks after contact, and resolves 4-6 weeks w/o a scar. Do the ulcers cause pain?
Definition
No, they are painless
Term
What happens in secondary syphilis?
Definition
The bacteria spreads in the blood, leading to systemic symptoms (widespread rash, condyloma latum, loss of eyebrows, lymphadenoapthy, weight loss, fever). Appears ~6 weeks after primary chancre has healed, secondary resolves in 6 weeks.
Term
What happens during latent syphilis?
Definition
secondary features are gone. serologic test may be positive. 25% have relapses. not infectious. 1/3 progress into tertiary syphilis.
Term
What are three general categories of tertiary syphilis?
Definition
1. Gummatous syphilis
2. Cardiovascular syphilis
3. neurosyphilis
Term
Pathophysiology and location of gummatous syphilis?
Definition
* Localized granulomatous lesions which eventually necrose and become fibrotic.
* skin: painless; bone: deep pain
Term
Can you treat gummatous syphilis?
Definition
Yes. Antimicrobials.
Term
What happens in cardiovascular syphilis?
Definition
Chronic inflammatory destruction of vasa vasorum supplying the aorta. Necrosis ofthe media layer of the aorta. Aortic aneurism. Cannot reverse with antimicrobials.
Term
Which two bacteria cause subacute meningitis with a predominance of lymphocytes?
Definition
Treponema pallidum
Mycobacterium tuberculosis
Term
A condition of tertiary syphilis, which affects the posterior column and dorsal roots of spinal cord?
Definition
Tabes dorsalis
Term
Symptoms of tabes dorsalis
Definition
* posterior column damage: disruption of vibratory and proproceptive sensations --> ataxia
* Dorsal root and ganglia damage --> loss of reflexes, loss of pain and temperature sensations
Term
What is "Argyll-Robertson pupil" which is present in both tabes dorsalis and general paresis?
Definition
Constricts during accommodation but does not react to light.
Term
What are the symptoms for early congenital syphilis (vertical transmission, w/n 2 years)
Definition
Like severe adult secondary syphilis. Mucous membrane involvement: snuffles
Term
Late congenital syphilis symptoms
Definition
Similar to adult tertiary syphilis. Cardiovascular sx are rare. Eight nerve deafness is common. Saddle nose (periosteal inflammation of teeth --> destroied cartilage of palate and nasal septum), saber shins, Hutchinson's teeth (upper central incisors widely spaced with a central notch on each tooth), eye disease
Term
When does the maternal syphilis affect the fetus?
Definition
after four months.
Term
Diagnostic tests for syphilis?
Definition
* Direct visualization of spirochetes during active stage
* nonspecific treponemal tests
* specific treponemal tests
Term
What are you looking for in nonspecific treponemal tests?
Definition
Damaged host cells from treponema palldium release lipids including cardiolipin and lecithin. The body makes antibodies for those lipids. These antibodies can be detectable in the serum/CSF.
* Veneral Disease Research Laboratory (VDRL)
* Rapid Plasma Reagin (RPR)
Nonspecific because 1% of general population is positive
Term
What are specific treponemal tests?
Definition
Detecting antibodies against the spirochetes. Indirect Immunofluorescent Treponemal Antibody-Absorption (FTA-ABS) test.
Pt. serum + nonpathological treponema (normal flora) --> Pt. serum + killed T. pallidum
Term
Treatment of syphilis?
Definition
Penicillin
If allergic, erythromycin and doxycyclin (dox not for fetus).
With Tx, nonspecific Ab decrease, specific Ab remain the same.
T. palldium killed by heat, drying, soap and water.
Term
What is Jarisch-Herxheimer Phenomenon?
Definition
Syphilis patients upon antibiotics-treatment develop acute worsening of symptoms: mild fever, chills, malaise, headache, and myalgia.
This is due to released pyrogen.
Term
Do subspecies of Treponema pallidum also cause syphilis?
Definition
Yes, but not STD. Skin ulcers present. 2' stage with widespread lesions. 3' stage with gummas of the skin and bones but w/o heart or CNS symptoms.
Term
What is "endemic syphilis" and what causes it?
Definition
Treponema pallidum Subspecies endemicum causes it. In deserts of Africa and Middle East, by sharing utensils. Oral mucosal ulcers.
Term
What is "endemic syphilis" and what causes it?
Definition
Treponema pallidum Subspecies endemicum causes it. In deserts of Africa and Middle East, by sharing utensils. Oral mucosal ulcers.
Term
What is gangosa?
Definition
Disfiguring lesion of the skin, caused by T. palldium Subspecies pertenue, destroying the bone, cartilage, and skin. Yaws. In moist tropical regions.
Term
What is pinta?
Definition
Term
What is pinta?
Definition
Rural Latin America. By Treponema pallidum Subspecies carateum. Purely skin lesions that turn red, blue with sun, and white (depigmented).
Term
Which vector and primary organism cause Lyme disease?
Definition
vector: Ixodes tick
organism: Borrelia burgdorferi (spirochete, gram-)
Term
Which disease causes the painless skin lesion, erythema chronicum migrans?
Definition
Lyme disease. Target shaped.
Term
Lyme disease has three stages. What are the characteristics of early localized stage?
Definition
- 10 days after tick bite, lasts for 4 weeks.
- erythema chronicum migrans
- flulike illness
- regional lymphadenopathy
Term
What are the target systems for early disseminated stage of Lyme disease?
Definition
1. Skin (erythema chronicum migrans. smaller than primary lesions, and diffuse.)
2. Nervous system (meningitis, CN 7 Bell's palsy, peripheral neuropathies)
3. Heart (AV nodal block, myocarditis, LV dysfunction)
4. Joint and muscle pain
Term
What are the manifestations of late stage Lyme disease?
Definition
Chronic arthritis (10% of untreated pt)
Encephalopathy
Term
Which anti-bacterials are used to treat Lyme disease?
Definition
Doxycycline and penicillin family
Term
What causes relapsing fever and how to treat it?
Definition
Borrelia recurrentis. Gram- spirochete. Keep changing antigen to escape host antibodies.
Tx: Doxycycline, erythromycin
Term
Which organism caused the following clinical picture?
Went swimming in a pool contaminated by dog urine. Abrupt onset of fever, headache, malaise, myalgia (thigh, lower back), conjunctivitis, photophobia. After a week, short afebrile period, then the same symptoms again.
Definition
Leptospira (aerobic spirochete, gram-)
Term
What causes Weil's disease (infectious jaundice, renal failure, hepatitis with jaundice, mental status changes, hemorrhages)
Definition
Leptospira interrogans (spirochete)
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