Bacteriology-49 Spirochetes*
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- What are the three pathogenic geni of Spirochetes
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Treponema
Borrelia
Leptospira - What are the basic characteristics of Spirochetes
- Spiral shaped organisms that don't gram stain, grow slowly in vitro or not at all
- What are the Pathogenic species of Spirochetes Treponema
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Treponema pallidum pallidum (called T. pallidum)
Treponema pallidum endenicum
Treponema pallidum pertenue
Treponema carateum - What Spirochete causes syphilis
- Treponema pallidum
- What spirochete causes Bejel
- Treponema pallidum subspecies endenicum
- What spirochete causes Yaws
- Treponema pallidum subspecies pertenue
- What spirochete causes Pinta
- Treponema carateum
- What are the pathogenic species of the spirochete genus Borrelia
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Borrelia recurrentis
Borrelia hermsii
Borrelia burgdorferi - What spirochete causes epidemic relapsing fever
- Borrelia recurrentis
- What spirochete causes Endemic relapsing fever
- Borrelia hermsii and related species
- What spirochete causes Lyme disease
- Borrelia burgdorferi
- What spirochete causes leptospirosis
- Leptospira interrogans (many different serovars)
- What are the characteristics of Spirochetes
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Spiral shaped bacteria. The spiral shape is determined by the rigid cell wall, which contains peptidoglycan. Length of organism and periodicity of coil differ among the genera and species within the family
Spirochetes are prokaryotes with inner and outer membranes in the cell envelope. They have periplasmic axial filaments that are related to flagella in other bacteria - What is the motility of spirochetes
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They exhibit corkscrew motility characterized by rotation and flexion.
They are capable of motility in media of high viscosity. This is believed to be important for their motility in vivo in infected tissues - How are the Spirochete species stained
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Treponemes are too thin for light micro. Use darkfield of DFA-TP
Borrelia use Giemsa or Wright
Leptospires are very thin and stain poorly. Use darkfield with silver - What are the nutritional requirements and cultivation of spirochetes
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Pathogenic Treponoma pallidum has not been grown in culture for long. Nonpathogenic is anaerobic
Some Borrelia can be cultivated. Fastidious and microaerophilic
Leptospira can be grown aerobically - What is the prevalence of Syphilis in the US
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7177 primary and secondary syphilis
413 congenital syphilis - What is the infectivity of Treponoma pallidum in Syphilis cases
- High. 50% infectious dose for humans is less than 100 organisms. Infects mucous membranes easily, especially if small cuts or abrasion are present
- How is Treponoma pallidum spread
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Sex most common
Congenital from mother to fetus in utero
Transmission by direct contact/inoculation is uncommon - What is the primary lesion in primary syphilis called
- A chancre. Systemic dissemination of spirochetes has already occurred when the chancre appears
- What are the characteristics of a chancre
- Painless, ulcer with a clean, hard base that develops within 2-10 weeks at the site of primary infection. Teeming with spirochetes. Heals spontaneously without treatment, but systemic infection persists
- What are the consequences of simultaneous infection by Treponoma pallidum and HIV
- Alters the course of syphilis and makes the disease more severe and more rapidly progressive
- What do the most common lesions of secondary syphilis involve
- The skin and mucous membranes. Lesions appear 2-10 weeks after disapperance of the chancre and may include papulosquamous rashes, mucous patches, and genital lesions called condylomata lata
- What are some uncommon secondary manifestions in secondary syphilis
- Meningitis, iritis, hepatitis
- How long does an early latent syphilis infection last
- Less than one year in duration. A late latent infection obviously lasts more than one year
- How often do relapses of secondary syphilis lesions occur
- 25% of patients, 90% during the first year of infection. Infectivity of body fluids declines with time during the latent stage of syphilis
- When does Tertiary syphilis occur
- Lesions of late syphilis typically develop years after infection and occur in about 33% of untreated patients
- What are the principal target organs in tertiary syphilis
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Cardiovascular system (syphilic aortitis)
Central nervous (asymptomatic neurosyphilis, meningovascular syphilis, tabes dorsalis, general peresis, optic atrophy)
Late benign syphilis (gummas) - Why are cultures of Treponoma pallidum not used for diagnosis of syphilis
- We can't cultivate T. pallidum
- What contributes to the tissue damage that occurs in lesions of syphilis
- Immune reactions to antigens of Treponema pallidum
- Does immunity in syphilis usually eradicate infection in the absence of appropriate antibiotic therapy?
- No, but it does decrease the probability of superinfection following repeated exposure
- In patients with Syphilis after appropriate treatment with antibiotics, what will be the reactivity in a nontreponemal test
- Usually Negative
- In a patient with syphilis after appropriate treatment with antibiotics, what will be the reactivity of a treponemal test
- Usually Positive
- What is the disadvantage of using a Treponemal test to diagnose syphilis
- They are quite specific for pathogenic treponemes, but do not distinguish between patients with syphilis, yaws, and pinta
- Nontreponemal antigen tests involve reactivity with what
- Cardiolipin antigens
- What is the drug of choice for syphilis
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Penicillin G. Treponema pallidum remains uniformly susceptible to penicillin. It has gained resistance to axithromycin
Use Ceftriaxone, tetracycline, or erythromycin when penicillin in contraindicated. Don't used spectinomycin - Where is the primary lesion in Bejel
- Oral cavity. It is caused by Treponema pallidum endenicum
- Where is the primary lesion in Yaws
- Skin (extremities), papillomatous. It is caused by Treponema pallidum pertenue
- Where is the primary lesion in Pinta
- Skin, erythematous papule
- What is relapsing fever
- A disease characterized by recurrent episodes of fever separated by asymptomatic intervals
- What is the epidemiology of Relapsing fever
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Louse borne (no animal reservoir)
Tick borne (transmitted from animals to humans). Occurs in endemic but not epidemic form - What microorganism establishes the initial infection in relapsing fever
- Borrelia. The organisms that are present in the blood during successive febrile episodes are antigenic variants of the Borrelia that established the initial infection
- What is the mechanism of antigen variation in relapsing fever
- Recombination of genes for serotype-determining proteins from silent loci into an expression locus (similar to pilus variation in Neisseria gonorrhoeae)
- What antibiotics are used for Relapsing fever
- Tetracyclines, erythromycin, and penicillin
- Where is Borrelia burgdorferi localized
- Northeastern coastal areas, Wisconsin, California, Oregon
- What is the most common arthropod borne infection in the US
- Lyme disease, transmitted by ticks
- What stage of ixodes scapularis development is responsible for transmission of lyme disease
- The nymphal stage (May through July)
- How is stage one (localized infection) of Lyme disease characterized
- Erythema migrans at site of tick bite
- How is stage two (disseminated infection) of Lyme disease characterized
- Secondary annular skin lesions and systemic symptoms such as severe malaise and fatigue
- How is stage three (persistent infection) of Lyme disease characterized
- Arthritis, meningoencephalitis, neuropathies
- How is Lyme disease clinically diagnosed
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Erythema migrans
Musculoskeletal, nervous or cardiovascular involvement with lab confirmation - What contibutes to the pathogenesis of Lyme disease
- Immune mechanisms
- How can various manifestations of Lyme disease be treated
- Oral antibiotic (doxycycline). Those with arthritis or neurological abnorms may required IV antibiotic treatment
- How do humans become infected with the spirochete Leptospira
- Contact with infected animals through exposure to urine in soiled or fresh water
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Acute febrile illness, accompanied by conjunctival suffusion, that may include jaundice and renal failure (Weil's disease) or meningitis
Diagnosis - Leptospirosis caused by the spirochete Leptospira interrogans