Term
single greatest biological warfare threat |
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Definition
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Term
bacillus anthracis characteristics and identifying features |
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Definition
gram+ rods
non-motile
nonfastidious
non-hemolytic
spore-forming (resistant to heat, UV, gamma-radiation, & disinfectants; may be dormant for decades; "medusa head" on agar surf) |
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Term
bacillus anthracis epidemiology |
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Definition
commonly infects grazing herbivores
more serious w/o animal vaccination
human-->human transmission: RARE
human infection (US): RARE |
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Term
bacillus anthracis virulence factors |
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Definition
2 large plasmids account for ALL virulence:
1. pXO1: toxin proteins (PA; LF; EF) combine to form binary exotoxins = lethal toxin/LeTx (PA+LF); edema toxin/EdTx (PA+EF)
*individually, toxin proteins harmless
2. pXO2: genes encode protein for capsule syn
*unique capsule: polyglutamate (antiphag) |
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Term
entry/action of anthrax toxin: PA binds anthrax receptor --> processed by furin on cell surf |
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Definition
--> PA oligomerizes => EF/LF binding sites --> toxins endocytosed --> PA conform chg w/ pH chg --> toxins in cytosol
EF (adenylate cyclase): releases cAMP
LF (protease): degrades MAPKK |
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Term
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Definition
cutaneous anthrax
common affected areas: head, neck, & extrem
description: nondescript 1* lesion (painless papule, no pus)
progression: w/in 2-3d vesicles --> central necrosis & drying => eschar (usually surrounded by eroded areas/edema- may be self-limiting)
left untx: bacteremic/fatal |
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Term
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Definition
inhalational anthrax (woolsorter's disease)
initial symptoms: flu-like (fever, cough, myalgia, malaise)
characteristic: widened mediastinum (this is where the org is prolif & prod toxins)
progression: 1-3d fulminant course (dyspnea, strident cough, chills, usually fatal)
associated: gastrointestinal & leptomeningeal lesions <= hematogenous spread |
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Term
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Definition
cause: eating anthrax-infected meat
fatality: 25-60%
symptoms: severe GI difficulty, vomiting blood, diarrhea, acute inflamm
(Bacillus anthracis)
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Term
anthrax hemorrhagic meningitis |
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Definition
fatality: 100%
symptoms: lots of edema, blood CSF (w/ gram+)
"Cardinal's cap" appearance (lots of hemorrhage of leptomeninges)
spreads: to CNS from any kind of anthrax infection |
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Term
identify cutaneous anthrax specimens |
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Definition
vesicular stage: vesicular fluid
eschar stage: eschar material |
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Term
identify gastrointestinal anthrax in these specimen: |
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Definition
blood, stool, rectal swab |
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Term
identify inhalational anthrax in these specimen: |
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Definition
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Term
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Definition
id bacillus anthracis on sheep blood agar
non-motile
non-hemolytic
irregularly round
medusa head colony (comma shaped projection)
PLET for isolation
bicarbonate agar => capsule formation |
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Term
identifying features of Bacillus cereus |
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Definition
beta hemolytic on sheep blood agar
string of pearls test-
motile
glutamyl-polypeptide capsule- |
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Term
Bacillus cereus virulence factors (2 toxins) |
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Definition
heat-labile (diarrheal): stim adenylate cyclase (=> cAMP); SLOW onset
heat-stable (emetic): RAPID onset |
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Term
ALL gram+ anaerobic spore formers |
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Definition
Clostridium
part of normal colonic flora
most abundant: C. ranosum, then C. perfringes
most pathogenic: C. perfringes |
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Term
Clostridium perfringes epidemiology |
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Definition
most predominant (spores/vegetative bacteria): serotype A in human fecal flora & in soil (most virulent)
growth time: very fast (3xs faster than E. coli)
infections endo/exogenous
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Term
pathogenesis of C. perfringes |
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Definition
growth requirements: ~14 AAs & 6 other factors (most body fluids are deficient of these materials EXCEPT necrotic tissues)
*produces ~12 toxins (alpha toxin=gas gangrene) |
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Term
types of diseases caused by C. perfringes |
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Definition
1. soft tissue infections: cellulitis, suppurrative myositis, myonecrosis (gas gangrene)
2. gastroenteritis: food poisoning, necrotizing enteritis |
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Term
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Definition
clostridial cellulitis
doesn't involve muscle/deeper tissue
anaerobic
less aggressive than gas gangrene
after surgery/trauma (dmg to arteries reduces 02 supply) |
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Term
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Definition
suppuration in muscle planes w/o necrosis or systemic symptoms |
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Term
gas gangrene=clostridial myonecrosis
what does the "gas" come from? |
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Definition
organism replication (there will be crepitus present)
extensive hemolysis
bacteria present
inflammatory cells absent
symptoms: shock, renal failure, death w/in 2d |
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Term
tx of clostridial myonecrosis |
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Definition
surgical debridement & frequently amputation |
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Term
2nd or 3rd most common cause of food poisoning in the US |
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Definition
Clostridium perfringes, usually type A
induces Ca++ dependent alteration in permeability
symptoms: epigastric pain, nausea, cramps, watery diarrhea |
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Term
other gastroenteritis caused by C. perfringes (other than food poisoning) |
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Definition
necrotizing enteritis (enteritis necroticans, pig-bel)
cause: strains prod beta toxin
occurs w/: high protein/trypsin inhibitor (sweet potato)
incr risk: decr intestinal proteases
symptoms: peritonitis, abdom px, vomiting, bloody diarrhea, shock
fatality: 50% |
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Term
septicemia from Clostridium perfringes |
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Definition
bacteremia: in pts w/ myonecrosis & necrotizing enteritis |
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Term
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Definition
Clostridium perfringes
non-motile, box-car shaped gram+ rod
*rod presence w/o leukocytes in specimen
nagler rxn+ (anti-alpha-toxin added to egg yolk agar cultures (on upper half)- prevents visible opacity <= lecithinase action of alpha toxin) |
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Term
Clostridium tetani characteristics & epidemiology |
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Definition
motile, spore forming, gram+ rod, anaerobe
common in soil
most cases (developing countries): newborns |
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Term
2 potent toxins of C. tetani |
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Definition
1. chromosomally encoded 02 labile hemolysin (tetanolysin): unclear role
2. plasmid encoded 02 labile neurotoxin (tetanospasmin-tetanus toxin): stationary phase, blocks release of inhibitory neurotrans |
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Term
C. tetani virulence factors |
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Definition
common entry to body: implanting spores in wounds
under anaerobic conditions: spores germinate --> produce toxins --> retrograde mvmt w/in CNS
char sympt: convulsive muscle contraction (lockjaw, back muscles)
cause of death: cardiac/respiratory complic |
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Term
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Definition
C. tetani
most common
masseter muscles (trismus, lockjaw); risus sardonicans
early signs: drooling, irritability, back spasm (opisthotonus) |
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Term
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Definition
clostridium tetani
confined to musculature of 1* site of infection |
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Term
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Definition
Clostridium tetani
head is the 1* site of infection
poor prognosis |
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Term
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Definition
tetanus neonatorum
clostridium tetani
common 1* infection site: umbilical stump (dirty tools to sever cord)
symptoms: excessive crying, trismus, tetanic spasms, opisthotonus
fatality: >90% (survivors have developmental defects) |
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Term
name the 4 types of C. botulinum diseases (all paralytic diseases) |
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Definition
1. foodborne botulism
2. infant botulism
3. wound botulism
4. inhalational botulism |
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Term
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Definition
C. botulinum
characteristic: symmetric descending paralysis
*flaccid paralysis
initially: blurred vision, constipation, abd px, no fever |
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Term
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Definition
inhalational botulism caused by Clostridium botulinum <= toxin can be aerosolized |
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Term
Clostridium difficile epidemiology |
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Definition
spores high conc in hospitals & LTCF (high antibiotic use)
risk of infection correl. to length of stay
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Term
virulence of C. difficile |
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Definition
spores survive gastric acidity (germinate in LGT)
2 toxins: enterotoxin A & cytotoxin B (disrupt epithel cell barrier)
*pseudomembranes seen on colon endoscopy |
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Term
steps to C. difficile colitis: |
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Definition
1. exposure to antibiotics
2. exposure to C. difficile capable of producing toxins
3. inadequate immune response (antibodies to toxin A-protective) |
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Term
2 most likely causes of colitis: |
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Definition
1. Clostridium difficile
2. Staphylococcus aureus |
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