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9 Cards in this Set
- Front
- Back
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mycoplasma overview
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-small prokaryotes
-no peptidoglycan cell wall -single plasma membrane -normal flora in mouth and genitourinary tract -insensitive to antibiotics that affect cell wall |
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mycoplasma organisms causing diseases
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-M. pneumoniae
-M. hominis -ureaplasma urealyticum |
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mycoplasma general features
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-highly pleomorphic-no cell wall
-lipid bilayer contains sterols -fastidious growth requirments-needs cholesterol -grows slowly, stains poorly -resistant to penicillin and antibiotics that affect cell wall -fried egg appearance on agar -P1 adhesin-binds to epithelial surfaces |
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M. pneumoniae epidemiology
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-transmitted by inhalation of aerosolized respiratory droplets
-person-to-person transmission -onset gradual-prodromal symptoms -few days of scant productive cough -atypical pneumonia: common cause of acute lower RTI in older children and young adults-walking pneumonia -happens throughout yr -infections from crowded schools, prisons, etc |
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M. pneumoniae pathogenesis
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-bacteria colonize between ciliated epithelial cells of the RT
-adherence leads to inhibition of ciliary movement->prolonged cough; mucoas desquamates-> mononuclear cell infiltrate->inflammatory damage rather than the organism itself -produces hydrogen peroxide which is cytotoxic and hemolytic to red blood cells causing hemoyltic anemia |
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M. pneumoniae clinical signs
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-upper RT and ear infections
-atypical pneumonia resembles others-legionella, chlamydia, coxiella, viruses; gradual nonspecific symptoms, dry/scanty productive cough; chest xray reveals patchy, diffuse bronchopneumonia; remission in 3-10 days -complications: rash, CNS, mild hemolytic anemia -immunity: Ab to the P1 adhesin and outer proteins, many false positives |
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mycoplasma diagnosis/treatment
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-grows slowly
-stains poorly -serodiagnosis-C' fixing Ab/PCR, 4-fold titer rise -cold agglutinins are detected by agglutination of O, Rh- rbc's at 4C |
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genital mycoplasmas
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-ureaplasma, and M. hominis natural flora of UG system
-difficult to establish causal role in infection -ureaplasma produces urease like helicobacter -can cause GU infection, endometritis, urethritis, PID |
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chlamydia overview
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-small bacteria
-obligate intracellular parasite; relies on host cell for ATP, NAD -grow in cytoplasmic vacuoles in host cells called inclusion bodies - |
