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45 Cards in this Set
- Front
- Back
Why are anaerobic infections usually polymicrobic?
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they wait till the facultative anaerobes use up all the O2 then they flourish
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Why is O2 so toxic to anaerobes?
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They don't have catalase and superoxide dismutase.... the result is the accumulation of H2O2 and superoxide
they lack this "detoxifying" pathway |
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What are the obligate anerobes?
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ABC's:
actinomyces, bacteriodes, clostridia |
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Clostridia morphology?
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anerobic gram + spore-forming rods
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Size of clostridium spores?
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larger than the cell
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Gas gangrene group:
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perfringens, novyi, septicum
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Diseases caused by gas gangrene group?
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Gas gangrene, anaerobic cellulitis, food poisoning
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Virulence factors of the gas gangrene group:
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alpha toxin which distrupts cell membrane (most important,
theta toxin enterotoxin |
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What is alpha toxin?
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lechthinase that distrupts cell membrane
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what is theta toxin?
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hemolysin that alters cepilarry permeability
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What causes Clostridium spore generation?
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the low pH in healing wounds
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What is the pathogenesis of C. perfringens, novyi, septicum?
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myonecrosis due to muscle and tissue destruction and separation via gas production
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What is treatment for gas gangrene?
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debridement, penicillin, hyperbaric O2
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exhibits stormy fermentation
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lecithinase
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BAP double zone of hemolysis caused by?
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presence of multiple hemolysins
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death of tetanous caused by what?
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exhaustion and respiratory failure
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Acquisition of tetanous neonatorum?
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Contamination of umbilical cord with C. tetani
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How is food poisoning caused by C. perfringens?
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enterotoxin is produced by vegetative cells in intesting, casuing diarrhea and nausea 8-24 hrs after eating
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Virulence factor of C. tetani
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tetanospasmin - released when bacteira dies
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What does tetanospasmin do inthe body?
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goes to CNS via motor nerves and inhibits release of GABA/Glycine, resulting in muscle spasm
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Morphology of C Tetani?
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gram + tennis shaped rod (head = terminal spore) without a capsule
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is C. Tetani motile or nonmotile?
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motile
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Immunizations C. Tetani with what and when?
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toxoid (inactivated with formalin) at:
6 weeks, 1, 4, 10 yrs |
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Treatment of C. Tetani?
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antitoxin, debridement, penicillin, and curare-like drugs
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When is antitoxin not needed if botulism is contracted?
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not needed for patients with immmunization/booster within 5 yrs of occurance
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Diseases caused by botulism?
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Flaccid paralysis, wound botulism, Infant botulism
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Incubation period of botulism?
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18-96 hrs
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Floppy baby?
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infant botulism
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Viurulence factor of botulism?
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destroyed by cooking but not stomach pH's. Toxin (which is phage-mediated) is released on death and autolysis
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Why are antibiotics bad for botulism?
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death of organism will cause release of more toxin
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What kinds of food will botulism flourish in?
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Spores will germinate on inadequately heated alkaline vegetables
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Action of botulism toxin?
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blocks ACh release at NMJ
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Cause of pseudomembranous colitis?
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C. difficile?
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Pathogenesis of C. difficile
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normally due to antibiotics, causing overgrowth. Toxin A and B released in stationary phase or after cell lysis allowing infiltratoin of pathogen.
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Treatment of C. difficile?
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discontinue antibiotics and substitute better drugs
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Outnumber all other bacteria in colon 10000:1
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bacteroides fragilis
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What is the common presentation of anaerobic causing disease?
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abscess formation
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mophology of B. fragilis?
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gram - rod, causes gram - infection in abdominal cavity
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morphology of actinomyces?
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filamentous gram + rod, normal oral flora
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How does actinomyces usually present?
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single organism after dental surgeyr
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#1 cause of infection in prosthetic joints? #2?
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1) propionibacterium acnes
2) S. epidermidis |
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morphology of propionibacterium acnes?
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gram + rod in normal skin flora
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Peptostreptococcus causes what?
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pleuropulm disease, brain abscessins, OBGyne infections
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Lumy jaw caused by?
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actinomyces
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morphology of peptostrptococcus?
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gram + coccus
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