spore forming gram positive bacilli Flashcards
spore forming gram positive bacilli
Bacillus subtilis
B. polymyxa
B. anthracis
B. cereus
Clostridium botulinum
C. tetani
C. perfringes
Clostrioides difficile
bacullus sp
spore forming, aerobic, gram positive, non swollen sporangium, occurring in chains
most are saprophytic
Sources of Antibiotics:
Bacillus subtilis,
Bacillus polymyxa
Bacitracin
Polymyxin
Bacillus anthracis
anthrax
Bacillus anthracis Pathogenesis
Vegetative cells have protein capsules (poly-γ-d-glutamic acid)
that resist phagocytosis.
Bacillus anthracis Toxins
- 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)
Bacillus anthracis Clinical Findings
- 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
Bacillus anthracis Treatment
must be started early
- Ciprofloxacin (DOC)
- Raxibacumab – treatment of and prophylaxis against
inhalational anthrax
Bacillus cereus Food Poisoning
- Emetic type – due to emetic toxin
- Diarrheal type – due to enterotoxins
Clostridium sp.
large spore-forming anaerobic, gram-positive, motile
(peritrichous) bacilli with swollen sporangium
* many decompose proteins or form toxins, or both
* saprophytic
Clostridium sp.
SPECIES
LOCATION OF SPORES
C. botulinum Subterminal
C. tetani Terminal (tennis
racket/drumstick)
C. perfringens Central/Subterminal
(club-shaped/bowling
pin)
Clostridium botulinum Transmission
spiced, smoked, vacuum packed, or canned alkaline foods that
are eaten without cooking
* honey (for infant botulism)
* tissue contamination with spores (wound botulism)
Clostridium botulinum clinical use
botox
SNARE PROTEINS
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
Clostridium botulinum Clinical Findings:
Botulism
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