large rods

endospore forming

distinctive Medusa Head colonies

gram positive

aerobic / facultative anaerobes

catalase positive, oxidase negative

motile (B anthracis is not)

hemolytic (common species)

B anthracis is not hemolytic

create amino acid-based capsule in vivo

extracellular anthrax toxin

plasmid based virulence triggered by temp and CO2 concentration

Gram positive selective media

Blood agar (detect hemolysis)

fast growth

create endospores that are resistant to heat, dryness, radiation etc

outside host environmental life cycle not clear

soil saprophytes

not much known about growth in environment

flooding may cause spores to surface

animals or people become exposed to spores

contact with soil in food or wound, inhalation

endospores enter the body with the soil

endospores are phagocytosed

endospores germinate inside phagocytes

phospholipase allows escape from phagocyte

vegetative cells grow rapidly and produce capsule and edema factor

this prevents phagocytosis of the vegetative cells

3 proteins on one plasmid:

edema factor: inhibits neutrophils

calmodulin dependent adenylate cyclase: mimics animal's second messenger.

lethal factor: zinc metalloprotease

creates hypoxia leading to tissue injury

protective antigen: cell binding and translocation component for other factors

the 3 components together cause increased vascular permeability and cell necrosis

other virulence factor: capsule. on a separate plasmid

cattle, sheep, deer

rapidly fatal

high fever, bleeding from orifices, shock, respiratory distress

after death: diagnose by dark, unclotted blood, incomplete rigor mortis, large jelly like spleen, widespread edema, high conc of bacteria in blood

caution should be taken; don't open the carcass to air and expose the endospores to oxygen.

collect blood that leaked out or get sample from thorax by needle aspirate

occurs in humans

"malignant carbuncle" - was thought to be cancer

"escar" wound, necrosis

used to come from infected animal products (clothing and leather)

treatment revolves around preventing septicemia

humans

woolsorter's disease: textile factories

terrorism

acute septicemia: horses

pharyngeal: pigs and dogs. tonsils, oral mucosa, lymph nodes affected

intestinal: man, pigs, horse. rare. no confirmed cases in US. 

infection does not usually result in protective immuity

this is because of the capsule that protects the bacteria

live endospores with detergent

uses a strain that still has the plasmid for 3-protein toxic portion but not capsule

the strain is avirulent because phagocytes can attack the vulnerable cells

a protective immune response is made that will be effective against the wild type's TOXIN

if the vaccine didn't have toxin then it wouldn't be effective

vaccinate healthy at risk animals in endemic areas

Quarantine infected for 30 days

use protective handling (carcasses and live)

treat with long acting antibiotics, vaccinate 8-12 days later

move to a new pasture

dispose of carcasses properly, disinfect contaminated materials