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29 Cards in this Set
- Front
- Back
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Obligate intracellular bacteria
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-Rickettsia, Coxiella, Chlamydia, Mycobacterium leprae
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Facultative intracellular pathogen
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-Legionella, Salmonella, Shigella, EIEC, M.Tb
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Epicellular
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-Bartonella, Mycoplasma
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Rickettsiae
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-small, Gram- bacilli
-arthropod borne (except coxiella/Q - cattle) -epidemiology = arthropod geography |
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Rocky Mountain Spotted Fever
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-R. rickettsii
-Atlantic, MO, KS, OK, OH, TX, AR, TN -April thru September (ticks) -severe w G6DH def -transovarial transmission in ticks -causes damage to BV, vasc SM, thrombocytopenia |
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Epidemic Typhus &
Brill Zinsser Disease |
-R.prowazekii
-human lice, but reservoir is man -BZ is the latent form |
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Ehrlichiosis
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-Ehrlichia chaffeensis
-Lone star tick, poor golf scores -fever, leukopenia |
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Rickettsia: pathogenesis
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-enter skin (tick bite), enter blood
-systemically infect endothelium -attachment induces phagocytosis -escape phagosome, replicate intracellularly (dictates pathology) |
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Rickettsia prowazekii:
epidemic typhus pathology |
-little cellular pathology
-large # of intracellular bacteria before host cell lysis |
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Rickettsia rickettsii:
Rocky Mountain Spotted Fever pathology |
-highly cytotoxic
-few R.rickettsii accumulate intracellularly -leave host via filopodia |
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Rickettsial Disease Pathology
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-endothelial injury
-edema, low BV, reduced organ perfusion, disordered fn (encephalitis, pneumonitis, hemorrhagic rash) |
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Ehrlichia:
Ehrlichiosis pathology |
-induce phagocytosis by leukocytes
-inhibits phagosome-lysosome fusion -survives and replicates in phagosome -cell and phagosome lysis (leukopenia) |
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RMF: diagnosis
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-history of exposure
-rash begins on feet/hands, moves in to trunk -vasculitis -confirm w fluorescent Ab test from punch biopsy, PCR |
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Epidemic typhus: diagnosis
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-history of exposure
-rash begins on trunk, moves out to feet/hands -stupor and delerium |
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Chlamydia: general
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-obligate intracellular (energy) parasite
-trachomatis, psittaci, pneumonia |
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Chlamydia trachomatis
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-ocular infections: trachoma - fibroblast invastion, vascularization
-STD: lymphogranuloma |
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C.trachomatis: serotypes & disease
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-A, B, Ba, C: Trachoma
-D-K, L1, L2, L3: inclusion conjunctivitis, cervicitis, salpingitis, proctitis, lymphogranuloma venereum |
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Chlamydia: epidemiology
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-trachomatis: flies, fingers, towels, cosmetics, sexual
-psittacosis: wild and domestic fowl -pneumoniae: Taiwan (prolonged bronchitis, sinusitis) |
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Developmental Cycle of Chlamydiae
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-EB: infectious form, no met activity, rigid cell envelop (DS -cysteine)
-phagocytized, vacuole forms -metabolic activation -> RB: DNA, RNA, protein synthesis -RBs divide -> EB |
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Host Response to Chlamydiae
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-infection -> formation of BV, CT, lymphocytic infiltrate
-chronic inflammation -Ab response does not help, immunization worsens infection |
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Chlamydiae: treatment
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-tetracycline, erythromycin, sulfonamides
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Chlamydia: diagnosis
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-inclusion bodies (EB ,RB) stain w iodine (contain glycogen)
-immunofluorescence of exudate, cell culture -DNA probes -measure ab, c' fixation |
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Mycoplasma
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-smallest free-living prok, no cell wall!!
-cocci, elongated filamentous -attachment organelles -"fried egg" -membrane = cholesterol (req sterols) -ureaplasma req urea |
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Mycoplasma: clinical presentation
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-atypical pneumonia (interstitial or bronchopneumonic)
-ab to RBC: cold agglutinins -UR dz, gradual onset -limited to one of lower lobes |
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Mycoplasma: Ureaplasma
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-ureaplasma urealyticum: nongonoccocal urethritis in men; spont. abortion, low birth weight, chorioanionitis
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Mycoplasma hominis
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-flora of vagina
-can invade internal genital organs -> PID, tubo-ovarian abscess, salpingitis |
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Mycoplasma: pathogenesis
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-surface parasite: local accumulation of toxic metabolites, lipid oxidation
-ag variation allows it to escape host immunity -host receptors: sialoglycolipids / proteins -adhesion = P1 |
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Mycoplasma: epidemiology
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-children 5-9 y/o
-M.pneumoniea: 8-15% pneumonias in young children; 15-50% in older adults -incubation period = 2-3wks |
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Mycoplasma:
culture, treatment |
-selective media, 8wk incubation
-ureaplasma makes media alkaline -rx: tetracycline, macrolides, newer quinolones -treat sexual partners too |
