Bacillus, Listeria, Corynebacterium Flashcards

1
Q
  • gram positive, non motile
  • facultative anaerobic rods
  • spores: form in rich media under aerobic conditions
A

bacillus anthracis

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2
Q

3 portals of entry for bacillus anthracis?

A
  1. cutaneous, 95% of cases
  2. inhalation: 5%, spores
  3. GI: very rare, ingestion of contaminated meat
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3
Q
  • woolsorters disease
  • flu like symptoms without runny nose, non productive cough
  • mediastinal widening
  • 100% mortality if not treated
A

inhalation anthrax

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4
Q

inhalation anthrax:

  • phagocytosis of inhaled spores by _______
  • transport to ________ lymph nodes
  • spore germination in lymph nodes
  • ______ production, hemorrhagic necrosis, bacteremia
A

alveolar macrophages

mediastinal

toxin production

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5
Q
  • acquired via ingestion of spores

- 2 forms: oropharyngeal with tonsillitis, intestinal with ulser/n/v/d or sepsis

A

GI anthrax

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6
Q
  • acquired via injured skin
  • painless papule develops into black necrotic ulcer with edema
  • may disseminate into septicemia
A

cutaneous anthrax

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7
Q

virulence factors of bacillus encoded on _______

A

virulence plasmid

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8
Q

virulence factors of bacillus?

A
  • antiphagocytic capsule- unusual poly D glutamic acid

- anthrax toxin: protective antigen, edema factor and lethal factor (adenylate cyclase activation, MAPKK inactivation)

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9
Q

lab diagnosis of bacillus anthracis?

A
  • driect gram stained smear of skin lesion, CSF or blood showing encapsulated, gram positive bacilli, with mucoid colonies
  • confirm with CDC
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10
Q

human vaccine for bacillus anthracis?

A

-cell free filtrate of attenuated strain containing protective antigen (PA)

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11
Q

drug of choice for bacillus anthracis?

A

ciprofloxacin

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12
Q
  • gram positive
  • spore forming
  • facultative anaerobe
  • motile, beta hemolytic
  • in contaminated food (rice)
A

bacillus cereus

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13
Q
  • emetic from contaminated rice, <6 hrs incubation, heat stable enterotoxin
  • diarrheal form: contaminated meat, >6 hrs incubation, 20-36 hours duration, heat labile toxin
A

gastroeneteritis, bacillus cereus

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14
Q

diagnosis of bacillus cereus?

A

culture and gram stain of contaminated food or infected specimens

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15
Q

drug of choice for bacillus cereus?

A

vancomycin or clindamycin

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16
Q
  • gram positive, facultative anaerobic
  • motile at room temp, tumbling motility
  • weakly beta hemolytic
  • grows at 4 degrees celsius
A

listeria monocytogenes

17
Q

early onset listeria in neonates?

A
  • acquired transplacentally
  • granulomatosis infanticeptica
  • 80% mortality
18
Q

late onset listeria in neonates?

A
  • acquired at birth or soon after
  • presents 2-3 wks after birth with meningoenecephalitis, septicemia
  • 70% mortality
19
Q

listeria infection initiates at _______ or ______ in Peyer’s patches in small intestine, intracellular replication so _______ immunity essential in clearing infection

A

enterocytes or M cells

cell mediated

20
Q

virulence factors of listeria?

A
  • internalins: mediate entry into non-phagocytic cells
  • listeriolysin O: pore forming hemolysin, activated by acidic pH
  • actin binding protein: mediates actin polymerization
21
Q

diagnosis of listeria?

A
  • cold enrichment grows at 4 degrees
  • weak beta hemolysis
  • tumbling motility in liquid culture, umbrella like growth
22
Q

drug of choice for listeria?

A

amipicillin or TMP-SMX

23
Q
  • gram positive rod
  • club shaped with volutin granules of Loffler medium
  • V and L shaped arrangements
A

corynebacterium diphtheriae

24
Q

diphtheria toxin:

  • B subunit targets?
  • A subunit ADP ribosylates _______ and shuts down protein synthesis
A
  • upper respiratory tract, heart, nerve cells

- elongation factor

25
Q
  • pseudomembranous pharyngitis
  • 1 week incubation-colonization of pharyngeal epithelial cells
  • toxin secretion –> sudden onset malaise, sore throat, low grade fever
  • grayish pseduomembrane
  • bull neck cervical adenitis and edema
  • complications: myocarditis, neuropathies
A

respiratory diphtheria

26
Q
  • colonization of skin, infection of subcutaneous tissue
  • papule: non healing ulcer
  • systemic disease due to exotoxin spread
A

cutaneous diptheria

27
Q

diagnosis of diptheria?

A
  • tellurite containing differential chocolate agar, black pigment
  • Elek test: demonstration of toxin
28
Q

drug of choice for diptheria?

A

erythromycin or penicillin