Flashcards in Microbiology - Soft Tissue Injury Deck (14)
C. tetani and C. botulinum are gram (+) anaerobes (rods) normally found:
in the environment ie soil
C. difficile, Bacteriodes, Prevotella, and Actinomyces are anaerobes (rods) normally found:
They are normal flora
C. difficile causes ______________ after antibiotic use, often nosocomial, change antibiotic and intervene surgically as necessary
What is the pathogenesis of C. tetani?
Vegetative cells release exotoxin tetanospasmin;
retrograde axonal transport;
Acts as protease, cleaves synaptobrevin (aka VAMP) in inhibitory motor nerves of the central nervous system
Without synaptobrevin, vesicles containing GABA and glycine cannot be released from affected neuron
Loss of central inhibitory activity on motor and autonomic neurons
What is the pathogen?
Local rigidity, difficulty swallowing
Strong muscle spasms/paralysis
Risus sardonicus (grimace)
Opisthotonus (strong arching of back)
Fractures, tendon ruptures from spasms
Terminal spore gives “tennis racket” appearance on microscopy
How are the botulinum exotoxin and tetanospasmin different/similar in their effect on the nervous system?
For botulinim toxin, Synaptobrevin is the same vesicle associated membrane protein (VAMP) targeted by tetanospasmin; at this different location the major affect is on release of acetylcholine --> flaccid paralysis
Floppy baby syndrome results from what infectious agent?
T/F: Laboratory studies like culture are useful for the diagnosis of Botulism.
C. perfringens is what kind of bacteria?
gram + spore forming rod
C. Perfringens produces 20+ toxins. Which is the main player?
Alpha toxin: lecithinase, necrotizing, hemolytic, cardiotoxic
What diagnosis is indicated by this finding?
Radiography may show “feathering” pattern of gas in soft tissue
What is the pathogenesis of C. perfringens food poisoning?
Germinating cells multiply in the small bowel
CPE enterotoxin of Type A strains destroys tight junctions between epithelial cells in gut, causing diarrhea and abdominal pain;
resolves in 24 hours
What is the pathogenesis of C. diff?
Germinating cells release Exotoxin A, which disrupts tight junctions, causing intestinal swelling and inflammation
Exotoxin B is the major toxin, disrupts the cytoskeleton by depolymerizing actin, kills the surrounding cells