Bacillus Flashcards
What is Bacillus also known as?
Anthrax
True/False: Bacillus forms a spore
True!!!!- They are spore forming
What is the main pathogen of Bacillus?
Bacillus Anthracis
What does Bacillus form?
Very long gram positive rods
Are Bacillus anaerobic or aerobic?
Facultative anaerobes
Bacillus is catalase _____ and oxidase ______
catalase positive and oxidase negative
How do you distinguish Bacillus from Clostridia?
Catalse test
If it bubbles you have Bacillus
If it doesn’t bubble you have clostridia
Where is Bacillus typically found?
soil and water
Why can Bacillus survive in the environement for long periods of time?
endospore is very hearty- can live forever
What plasmids does Bacillus produce?
pX01 and pX02
plasmids makes them very virulent
PX02 encodes for the capsule
What regulatory proteins does Bacillus have?
AtxA- anthrax toxin activator
AcpA- Anthrax capsule activator
What does the capsule do in Bacillus
inhibits phagocytosis
composed of D-Glutamyl polypeptide
non encapsulted isolates are essentially _____
avirulent
vaccine can get a good reaction against an avirulent bacillus anthracis
What is the two toxins of Bacillus?
Lethal toxin and Edema toxin
What is Lethal toxin composed of?
Protective antigen (PA) and lethal factor (LF)
LF is responsible for the toxic activity
Protective antigen is for adhesion
What does Lethal toxin cause at high and low doses?
At low doses causes cytokine storm- multi organ failure and death
At high doses- apoptosis of macrophages
What is the lethal toxin and edema toxin under the control of?
AtxA
what is the edema toxin composed of?
protective antigen and edema factor
What does edema factor cause?
electrolyte and fluid loss in affected cells
Why do we incinerate carcasses that have bacillus anthracis?
because the vegetative cells can survive for 2 weeks in unopened carcass
what kind of soils does bacillus anthracis love?
calcium rich soils
calcium plays a huge rold in formation of the endospore
Spores can persist for ____ in dry environment
decades
Does Bacillus anthracis have a large variability?
No- they have spores that live forever on the ground so they don’t need to be variable
What species are resistant to Bacillus?
Carnivores are fairly resistant
Birds are totally resistant
What is the infectious unit of the Bacteria?
Endospore
What are the modes of transmission of Bacillus?
ingestion of contaminated feed and water- bone meal and animal feed supplements are common vehicles
wound infection
arthropod bites
Sheering sheep- wool may have anthrax
Pathogenesis of Bacillus
- animal ingests the spore or it enters a wound
- Bacteria phagocytosed by macrophages- spores germinate into vegetative form
- due to environmental cues the toxins will start getting released
- Bacteria escapes its vegetative form from the phagolysosome and causes cytokine storm
- fluid and elecrolyte loss via edema factor
- multi organ dysfunction, shock, and depletion of clotting factor
when does the vegetative form start?
Once the spore gets into the tissue
What causes bleeding at body orifices?
Lethal factor
This is followed by shock and death
What are some post mortem findings with Bacillus?
ABSENCE OF RIGOR MORTIS
non clotting blood- bleeding from the nose and other orfices
hemorrhage
friable spleen
Who are the most susceptible species for Bacillus?
Sheep and Cattle
They get Septicemia!!!
True/ False: Bacillus has a long incubation period?
False- very short incubation period 1-5 days
sometimes animals can die without clinical signs
What are clinical signs in horses with Bacillus?
Colic, diarrhea, and edema
What clinical signs are produced in swine with Bacillus?
obstructive edema may cause death
hemorrhagic enteritis
Pathogenesis of Cutaneous Anthrax
- bacteria enters through cut or abrasion
- incubation for a few days- papule forms
- papule becomes blister that ulcerates
- lesion dries and leaves necrotic area called BLACK ESCHAR
low fatality
What causes gastrointestinal anthrax and what is the outcome?
consumption of contaminated meat
Septiemia can occur
Comes with a high fatality rate! (25-60%)
What are the characteristic of inhalation anthrax?
Mortality is 100%
pulmonary edema and hemorrhagic pneumonia
meningitis and hemorrhage in the brain
sometimes incubation can be really low even with high doses
Does Bacillus typically infect from animal to animal?
No- not unless you have a lot of infected carcasses around
What kind of sera can help alleviate disease?
Hyper immune sera
What kind of vaccine can be used that lacks the pX02 plasmid?
Sterne strain vaccine
True/False: Field necrospsys should be performed on carcasses
False: NO FIELD NECROPSY- you will expose yourself and the environment
What stain is used to detect Bacillus?
McFadyeans methylene blue - you can see the capsule
Picture of Bacillus anthracis to know
Bacillus is a facultative anaerobe, when it is aerobic and doesn’t form a capsule what appreance does it have on growth media?
medusa head
What test is characterized by blebbing?
String of Pearl test
What thermopreciptation test is very specific for bacillus anthracis?
Ascoli Test
What is the treatment for Bacillus?
antimicrobial treatment with antiserum - Penicillin G
animals are isolated and treated- quarantined for 3 weeks
Bacillu causes a _____ disease
Reportable
incinerate the carcass
