spore forming gram positive bacilli Flashcards

1
Q

spore forming gram positive bacilli

A

Bacillus subtilis
B. polymyxa
B. anthracis
B. cereus

Clostridium botulinum
C. tetani
C. perfringes

Clostrioides difficile

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2
Q

bacullus sp

A

spore forming, aerobic, gram positive, non swollen sporangium, occurring in chains
most are saprophytic

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3
Q

Sources of Antibiotics:
Bacillus subtilis,
Bacillus polymyxa

A

Bacitracin
Polymyxin

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4
Q

Bacillus anthracis

A

anthrax

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5
Q

Bacillus anthracis Pathogenesis

A

Vegetative cells have protein capsules (poly-γ-d-glutamic acid)
that resist phagocytosis.

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6
Q

Bacillus anthracis Toxins

A
  • Protective antigen (PA)
     binds to specific cell receptors
     after proteolytic activation, forms a membrane channel that mediates
    entry of EF and LF into the cell
  • Edema factor (EF)
     an adenylate cyclase
     with PA, forms edema toxin, which causes cell and tissue edema
  • Lethal factor (LF)
     With PA, forms lethal toxin, which is a major virulence factor and causes
    death in infected animals and humans (impairs both innate and adaptive
    immunity)
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7
Q

Bacillus anthracis Clinical Findings

A
  • Cutaneous Anthrax (95%) – entry of spores through the skin
     Pruritic papule → vesicle/s → necrotic ulcer (central black eschar) →
    healing
    by granulation (scar)
  • Inhalational Anthrax/Woolsorter’s Disease (5%) –
    entry of spores into the lungs

Gastrointestinal Anthrax (rare) – entry of spores through the mucous membranes
 abdominal pain, vomiting, and bloody diarrhea

Injection Anthrax – entry of spores through injections
 extensive, painless, SC edema and absence of the eschar of
cutaneous anthrax
 may progress to hemodynamic instability due to septicemia

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8
Q

Bacillus anthracis Treatment

A

must be started early

  • Ciprofloxacin (DOC)
  • Raxibacumab – treatment of and prophylaxis against
    inhalational anthrax
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9
Q

Bacillus cereus Food Poisoning

A
  • Emetic type – due to emetic toxin
  • Diarrheal type – due to enterotoxins
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10
Q

Clostridium sp.

A

large spore-forming anaerobic, gram-positive, motile
(peritrichous) bacilli with swollen sporangium
* many decompose proteins or form toxins, or both
* saprophytic

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11
Q

Clostridium sp.

A

SPECIES
LOCATION OF SPORES
C. botulinum Subterminal
C. tetani Terminal (tennis
racket/drumstick)
C. perfringens Central/Subterminal
(club-shaped/bowling
pin)

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12
Q

Clostridium botulinum Transmission

A

spiced, smoked, vacuum packed, or canned alkaline foods that
are eaten without cooking
* honey (for infant botulism)
* tissue contamination with spores (wound botulism)

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13
Q

Clostridium botulinum clinical use

A

botox

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14
Q

SNARE PROTEINS

A

proteins that allow the fusion of vesicles and
plasma membrane

v-SNARE – in the vesicles
Synaptotagmin

t-SNARE – in the target plasma membrane
Syntaxin
SNAP-25

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15
Q

Clostridium botulinum Clinical Findings:
Botulism

A

flaccid paralysis
* visual disturbances (incoordination of eye muscles, double vision), inability to swallow,
and speech difficulty, which are progressive
* death from respiratory paralysis or cardiac arrest
* no fever
* infants: “floppy baby” syndrome
 poor feeding, weakness, and signs of paralysis

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16
Q

Clostridium botulinum Treatment and Prevention

A
  • Treatment
     Mechanical ventilator
     Antitoxin
  • Prevention
     Boil canned goods before eating
     Do not eat bulging canned goods
17
Q

Clostridium tetani Transmission

A
  • commonly found in soil, dust, and animal manure
  • introduction of spores through wounds
18
Q

Clostridium tetani Toxin:

A

Tetanospasmin

  • Larger peptide
    d γ-aminobutyric acid
    (GABA)–secreting neurons from the brainstem
  • Smaller peptide
    also called VAMP2
19
Q

Clostridium tetani Clinical
Findings:

A

Tetanus

pastic paralysis
* trismus/lockjaw
* risus sardonicus/sardonic smile (grin + raised eyebrowns)
* opisthotonos/hyperarching of the back
* death from interference with the mechanics of respiration
* neonatal tetanus – due to cutting of umbilical cord with contaminated instruments

20
Q

Clostridium perfringens Toxins

A

Alpha toxin
 a lecithinase – hydrolyzes lecithin to phosphorylcholine and diacylglycerol
 aggregates platelets, causing thrombus formation and poor
perfusion of tissues

  • Theta toxin
     a hemolysin – forms pores in cell membranes
     produces target/double hemolysis on BAP
  • Epsilon toxin
     causes edema, hemorrhage
20
Q

Clostridium tetani Treatment and
Prevention

A

Treatment
 Penicillin
 Muscle relaxants
 Sedation
 Mechanical ventilator
 Antitoxin

  • Prevention
     Active immunization with toxoids
     Aggressive wound care
     Prophylactic use of antitoxin
     Administration of penicillin
21
Q

Clostridium perfringens Enzymes

A
  • DNAse
  • Hyaluronidase
  • Collagenase
22
Q

Clostridium perfringens Clinical Findings:

A

Gas Gangrene

  • clostridial myonecrosis
  • crepitation in the SC tissue and muscle, foul-smelling discharge, rapidly progressing necrosis, fever, hemolysis, toxemia, shock, and death
22
Q

Clostridium perfringens Treatment

A
  • Prompt and extensive surgical debridement
  • Excision of devitalized tissue
  • Penicillin
  • Hyperbaric oxygen
  • Antitoxin
  • Amputation
22
Q

Clostridium perfringens Pathogenesis

A
  • Spores reach tissue either by contamination of traumatized
    areas (soil, feces) or from the intestinal tract.
  • Spores germinate, vegetative cells multiply,
    carbohydrates in tissue, and produce gas.
    ferment
  • Distention of tissue, interference with blood supply, secretion
    of necrotizing toxins and hyaluronidase favor the spread of
    infection.
  • Tissue necrosis extends, leading to hemolytic anemia, severe
    toxemia and death.
23
Q

Clostridioides difficile
Clinical Findings:

A

Pseudomembranous Colitis

microabscesses in patients who have diarrhea and have been given antibiotics (ampicillin, clindamycin, fluoroquinolones)

 may be watery or bloody, and frequently has
abdominal cramps, leukocytosis, and fever

Part of GI flora

24
Q

Clostridioides difficile Treatment

A
  • Discontinue offending antibiotic
  • Vancomycin (DOC), Metronidazole
  • Fecal transplant