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23 terms

MHR: Anaerobes

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What is the name for organisms that cannot utilize oxygen as their terminal electron acceptors. These organisms are killed by the presence of toxic oxygen intermediates
Anaerobes
One explanation as to why anaerobic organisms are killed by oxygen is what?
Anaerobes lack the necessary enzymes such as catalase, peroxidase, superoxide dismutase to break down toxic intermediates (such as O2-, H202, OH radical)
What is an example of a gram (+) anaerobic spore forming rod. Box-car shaped, catalase negative. Some species are found normal flora in humans.
Clostridia
What is the gram positive anaerobe that has normal flora in the vagina and GI tract, but can cause gas gangrene, cellulitis, sepsis, and food poisoning.
Clostridium perfringens
What is the anaerobe called which contains at least 12 exotoxins, with alpha toxin being the most important.
Clostridium perfringes
What is the name for the small, heat labile protein that binds to receptors on the epithelial cell surfaces and disrupts ion transport through ileum leading to loss of fluid and intracellular proteins
Enterotoxin
What is the name of the enzyme that degrades the viscous DNA in necrotizing tissue or exudates, aiding the spread of infection
DNase
What is the name of the enzyme that disrupts the organization of ground substance, facilitating the spread of infection
Hyaluronidase
What is the name for gas gangrene
Myonecrosis
What is the disease that results most often from C. perfringens; in this, toxins and enzymes mediate tissue destruction and spread of infection; muscle becomes necrotic. toxins can be carried to other organs causing systemic effects such as shock, renal failure, and can lead to loss of limb or death
Gas gangrene (myonecrosis)
What is the Clostridium per fringes infection that infect connective tissue along fascial planes but does not involve invasion of muscle tissue
Cellulitis
What is a common cause of food poisoning that presents with nausea, abdominal cramps, and diarrhea 8-18 hours after eating
Clostridium perfringes
What is the organism that causes is used by plastic surgeons and dematologists
Clostridium botulinum
What is clostridium botulinum pathogenesis
1. Botulinum toxin passes from gut into circulation.
2. Botulinum toxin is taken up by axon and cleaved into light and heavy chain
3. Light chain of botulinum toxin interrupts signal transduction by blocking release of acetylcholine from synaptic vesicles
What are the three forms of botulism
Classic - food
Infant - food
Wound
What is the form of botulinum in which spores germinate to vegetative form which produces toxins most associated with home canning. Ingestion of preformed toxins causes this form of botulinum. Symptoms include double vision, paralysis, and can lead to death
Classic botulinum
What is the form of botulinum which occurs when infants ingest foods that contain spores. Symptoms include constipation, feeding problems, lethargy, and poor muscle tone. Infant can become paralyzed including respiratory arrest.
Infant Botulinum
What is the form of botulinum which occurs when wounds become contaminated with spores that germinate and produce toxins. Associated with injection of illegal drugs
Wound botulinum
What is the organism with the following epidemiology: anaerobic, gram +, spore forming bacteria, found in soil, animal feces' most cases due to puncture wounds, injection of illegal drugs can lead to this
Clostridium tetani
What is the pathogenesis of C. tetani
1. Toxin synthesized at wound site, and transmitted to peripheral motor neuron terminals and spinal cord
2. Interferes with inhibitory neurotransmitter release to block inhibitor impulses
3. Leads to unopposed muscle contraction and spasm
What organism is a major cause of nosocomial infections, and is a minor component of the normal flora of the intestines. It causes antibiotic associated diarrhea and pseudomembranous colitis
C. difficile
What organism produces two toxins A & B and forms pseudomembranes in severe disease
C. difficile
What is the predominant bacteria found in the human colon. It is anaerobic and gram (-). Most of these infections are due to B. fragilis group. It is the major cause of intra-abdominal infections, pelvic inflammatory disease, and pelvic abscess
Bacteroides