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55 Cards in this Set

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  • Back
What are the three pathogenic geni of Spirochetes
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
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
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
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
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
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
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
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
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
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
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
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
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
Acute febrile illness, accompanied by conjunctival suffusion, that may include jaundice and renal failure (Weil's disease) or meningitis
Leptospirosis caused by the spirochete Leptospira interrogans