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Bacillus anthracis (Anthrax)
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Bacillus anthracis and p. 135
capsule composition p. 121
exotoxin production p. 130
spore formation p. 129
With Bacillus anthracis, bacillus means little rod and anthracis means coal.
Not a good reputation!
Ok, now B. Anthracis has a thick peptidoglycan cell wall, which takes in purple dye when Gram stained - so this is a gram-positive bacteria.
Also, it is a non-motile bacteria and a facultative anaerobe, meaning it can survive with or without oxygen.
B. Anthracis is also a non beta-hemolytic bacteria, because when cultivated on a medium called blood agar, B. Anthracis colonies don’t cause beta-hemolysis, where hemolysis, or breakdown of the red blood cells that surround the colonies makes the blood agar change color from red to transparent yellow.
Finally, Bacillus Anthracis is a spore-forming bacteria, so it can undergo endosporulation when it feels threatened by the environment, like when the temperature becomes too high or too low, in case of extreme dryness, or when there’s harmful radiation around.
Endosporulation means that the bacteria starts by replicating its DNA, and then it forms a wall inside the cell, isolating the big portion of the cell, let’s call it the mother cell, from the small portion of the cell.
Next, the forespore gets completely engulfed by the mother cell, something like a cell within a cell.
Finally, inside the dying mother cell, the forespore loses water and accumulates calcium, and at the same time gets wrapped in a super tough cortex from the dying mother cell.
At this point, the endospore is able to resist heat, due to the presence of dipicolinic acid found in the core of the Bacillus anthracis spore, harsh chemicals, digestive enzymes, and even antibiotics.
Bacillus anthracis is an encapsulated, spore-forming, gram-positive bacteria bacterium that's known to cause anthrax. Anthrax can cause severe pulmonary, gastrointestinal, or cutaneous illnesses in humans. Anthrax can be transmitted via ingestion, inhalation, and skin invasion by the bacteria or its spores, often via direct interaction with infected animals.
It is more seen in agricultural regions where livestock are infected with the bacteria. Depending on the affected organs, it can present with a black necrotic skin lesion; fever, respiratory distress, abdominal pain, septic shock, and death if bloodstream infection occurs.
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