Bacillus And Clostridium (Spore-Forming Rods) Flashcards
How is B.anthracis transmitted?
Endospores:
- Cutaneous
- Inhalation
- Ingestion
Where is B.anthracis found?
Herbivores (zoonotic):
- Sheep
- Goats
- Cattle
What is the metabolism of B.antracis?
Aerobic - but since it can grow without oxygen, it is classified as facultative anaerobic.
What is the virulence of B.anthracis?
- Unique protein capsule (polymer of gamma-D-glutamic acid): antiphagocytic.
- Non-motile
- Virulence depends on acquiring 2 plasmids. One carries the gene for the protein capsule; the other carries the gene for its exotoxin.
What are the toxins of B.anthracis?
Exotoxin: 3 proteins.
- Protective antigen (PA)
- Edema factor (EF)
- Lethal factor (LF)
What can B.anthracis cause?
- Cutaneous (95%) –> painless black vesicles - fatal if left untreated.
- Pulmonary (woolsorter’s disease).
- GI: Abdominal pain, vomiting, and bloody diarrhea.
Does infection with B.anthracis result in permanent immunity, if the patient survives?
Yes
How do we identify B.anthracis?
- Gram stain
- Culture
- Serology
- PCR of nasal swab
How is B.cereus transmitted?
Via endospores.
What is the metabolism of B.cereus?
Aerobic
What is the virulence of B.cereus?
- No capsule
2. Motile
What are the toxins of B.cereus?
Enterotoxins:
- Heat labile –> Similar to E.coli or enterotoxin of cholera.
- Heat stable –> Syndrome similar to that of S.aureus food poisoning, but with limited diarrhea.
What can B.cereus cause?
Food poisoning:
- Nausea
- Vomiting
- Diarrhea
How do we identify B.cereus?
Culture specimen from suspected food source.
Where is C.botulinum found?
- Soil
- Stored vegetables - home-canned, zip-lock storage bags.
- Smoked fish
- Fresh honey –> infant botulism.
How is C.botulinum transmitted?
Via endospores.