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51 Cards in this Set
- Front
- Back
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What does a spore appear like under the microscope?
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Refractile
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What are some of the mechanisms by which spores are able to survive in the environment?
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-Resistant to enviornmental hot/cold
-Can't be dessucated -Don't replicate/no ATP |
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What acid is in spore walls?
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Dipicolinic acid
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What are some toxin-producing clostridial diseases?
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Wound botulism
Tetanus Pseudomembranous colitis Gas gangrene |
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That bug causes tetanus?
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Clostridium tetani
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What disease does Clostridium tetani cause?
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Tetanus
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What is the source of bacteria in tetanus?
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Spores found in the soil
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What are some of the symptoms of tetanus?
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Spastic paralysis
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What disease does Clostridium botulinium cause?
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Botulinium
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What bug can cause flaccid paralysis of the muscles?
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C. botulinium
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What is the source for C. botulinium?
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Spores found in food
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What are the symptoms of an infection of C. botulinium?
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Flaccid paralysis
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What is the mechanism of muscle paralysis by C. tetani?
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Toxin-mediated - protease
The toxin cleaves the SNARE proteins in inhibitory neurons in the PNS They would fire constantly. |
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What is the mechanism of muscle paralysis by C. botulinium
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Toxin mediated - protease
SNARE proteins are cleaved in PNS motor neurons; can't release ACh Can't fire - flaccid paralysis |
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What is the mechanism of prevention of tetanus?
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Vaccine
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What is the serious disease caused by Clostridium perfringens?
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Gas gangrene
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What bug can cause gas gangrene?
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Clostridium perfringens
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What are the toxins found in C. perfringens?
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Alpha toxin: hydrolyzes phospholipids
Hydrolases Proteases |
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What is the more benign disease caused by C. perfringens?
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Food poisoning via heat resistant spores
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What Clostridium species can cause food poisoning?
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C. perfringens
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What is a disease caused by C. difficile?
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Pseudomembranous colitis
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What bug can cause pseudomembranous colitis in a person on antibiotics?
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Clostridium difficile
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Do all strains of C. difficile cause pseudomembranous colitis?
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No; some strains are non-toxigenic
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Is pseudomembranous colitis caused in a normal individiual by this bug?
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C. difficile
No; you need to have a destruction of the normal microbiota |
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What is a mechanism of spread of C. difficile?
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Spores
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What are the three toxins found in C. dificile
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Toxin A
Toxin B Binary toxin |
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What does C. difficile Toxin A do to cells?
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Cell retraction and rounding via destruction of the tight junctions between cells
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What does C. difficile Toxin B do to cells?
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Initiates apoptosis
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What is the activity of the C. difficile binary toxin?
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ADP-ribosyl transferase that disrupts the actin cytoskeleton?
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What is a use of the botulinum toxin?
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BOTOX!
Get rid of them wrinkly wrinkles! |
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What is the bacteriology of bacteroides fragilis complex?
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Gram-negative
LPS lacks endotoxic activity Penicillin resistant |
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Where is Bacteroides fragilis found?
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Intestine
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What is the bacteriology of porphyromonas/prevotella?
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Gram-negative
LPS HAS penicillin Sensitive to penicillin |
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Where is porphyromonas/prevotella found?
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Oral cavity
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What are the mechanisms of pathogenicity by Bacteroides fragilis?
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Polysaccharide capsule
Neuraminidase Oxygen-resistant (has superoxide dismutase, catalase) |
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What is the mechanism of B. fragilis genetic variation on the capsule?
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Flipping of the promoters of the capsule genes
d |
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What is a problem that non-enterotoxigenic Baacteroides fragilis can cause?
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Abcesses; anaerobic environment means that they're able to grow well
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What does the polysaccharide capsule of B. fragilis cause?
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Abscess formation
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What is the function of neuraminidase in this anerobic bacteria?
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B. fragilis
Uses sialic acid as an energy source. |
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What is a medically important anaerobic gram positive cocci?
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Peptostrptococcus
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What is a medically important anaerobic gram-negative cocci
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Veillonella
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What is a medically important anaerobic gram-positive, spore forming rod?
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Clostridium
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What are four medically important, anaerobic gram-positive, non-spore forming rods?
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Actinomyces
Mobiluncus Lactobacillus Propionibacterium |
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What are four medically important, anaerobic gram-negative rods?
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Bacteroides
Fusobacterium Porphyromonas Prevotella |
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What is a medically important anaerobic gram-negative rod?
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Bacteroides fragilis
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What is a common cause of an abscess?
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Introduction of microbial flora to a normally sterile site
Via laceration, perforation of mucous membranes |
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Why can't anaerobes grow in oxygen?
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Toxicity of metabolic byproducts (O2-, H2O2)
Lack enzymes Bacterial enzymes require reduced environment |
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What enzymes do anaerobic bacteria lack?
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Superoxide dismutase
Hydrogen peroxidase Catalase/peroxidase |
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What is the bacteriology of clostridium?
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Anaerobic
Large Gram positive bacilli Spore forming Toxin producing |
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What is the model of action of the toxin secreted by enterotoxigenic Bacteroides fragilis?
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Secreted zinc-dependent metalloprotease
Meadiates cleavage of E-cadherin--> disruption of tight junctions Simulates IL-8 production by intestines |
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Other than abscesses, what other problems can an enterotoxigenic version this gram negative anaerobic bacteria cause?
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Bacteroides fragilis
Diarrhea |
