Bacillus Flashcards
How does Bacillus anthracis look on gram stain?
it is gram positive, with large rods
What type of cultures does B. anthracis form?
typical ground glass surface, non-hemolytic, and most produce spores
What type of toxin does B. anthracis produce?
a three component toxin
What is the toxin of B. anthracis dependent on the presence of?
large plasmid (pXO1)
What are the three components of the B. anthracis toxin?
protective antigen (PA), edema factor (EF), and lethal factor (LF)
What does PA do?
it acts as a binding unit - it attaches to the cell receptor, undergoes proteolytic cleavage, remains bound to the cell and serves as a docking station for EF or LF
What does EF do?
it activates adenylate cyclase and dramatically interferes with cell function
What does LF do?
it proteolyticly cleaves the (MAPK/ERK kinase) involved in signal transduction in CD4 lymphocytes and fibroblasts. It also inhibits IL-2 production and regulation of the immune response
When is the capsule of B. anthracis present?
when the culture is grown on media containing bicarbonate or 50% serum agar in 5% CO2
When do B. anthracis spores usually form?
when they are exposed to O2
What is the capsule of B. anthracis composed of?
poly-d-glutamic acid
Where is B. anthracis commonly found (geographically)?
tropics or subtropics
What environments are incubators for B. anthracis?
soil high in N and soil where there is alternate flooding and drying
What does B. anthracis grow in specifically (environmental)?
decaying plant material
What is species are most often affected by B. anthracis?
ruminants and other herbivores
What does B. anthracis cause in cattle and sheep?
acute to peracute septicemia, toxemia, and death
What does B. anthracis cause in horses?
colic, edema of head, neck, and shoulders
Where is B. anthracis usually localized in swine, dogs, and cats?
the pharyngeal area
What does B. anthracis cause in humans?
malignant carbuncle, gastroenteritis, and respiratory infection
What is the respiratory form of B. anthracis called in humans?
Woolsorter’s disease
Which humans typically get B. anthracis?
those that work with hides, wool, and hair from infeected animals
Is there a vaccine for B. anthracis?
yes, but it doesn’t work well for Woolsorter’s disease
If a carcass is suspected to have anthrax what should you not do?
open it because it allows it to sporulate
How can you safely diagnose B. anthracis?
take an ear slice and do an impression smear or use a handheld PCR
How does immunity from B. anthracis develop?
the host needs to survive the infection
What is the vaccine for B. anthracisin animals made out of?
modified live, acapsular mutant
What is the vaccine for B. anthracis in humans made of?
killed bacterin based on protective antigen
When is it recommended for anthrax immunization?
30 days before anthrax season in endemic areas
Where are the endemic areas for anthrax?
Minnesota, montana, manitoba, and North and South Dakota
When does immunity wane (after vaccination)?
6 months
How do you treat for B. anthracis infection in animals?
penicillin or tetracycline
How do you treat for B. anthracis infection in humans?
penicillin, tetracycline, and ciprofloxacin
How is anthrax controlled?
burning or deep burial of infected carcasses
What ‘disease’ is B. cereus commonly known for?
food poisoning
What infectious diseases does B. cereus cause in humans?
abscesses, cellulitis, bacteremia, septicemia, urinary tract infections - mostly in immunocompromised hosts
Besides humans, what does B. cereus cause infectious diseases in?
guinea pigs, and mastitis in cattle
What toxins does B. cereus have?
emetic toxin, lethal toxin, and cereolysin
What virulence plasmids does B. cereus var anthracis have?
pXO1 and pXO2 - plasmids of B. anthracis
What disease is B. subtilis a cause of?
disease in immunocompromised humans and heroin addicts
What is B. thuringiensis?
an insect pathogen
Why is B. thuringiensis a natural insecticide?
because the parasporal body is toxic - the cry and cyt proteins are pore-forming toxins withreceptors on insect gut epithelium
